Blaze Pascal
As many of you know, I own the full source to TPC.EXE - The DOS Pascal Compiler. What you didn't know...
It's 32bit and Makes 16bit DOS Executables
Recently, I asked Claude to review my 32bit source, find any bugs. Over the 8 months of working with Claude, it was able to identify 4 bugs. They all presented themselves as lock-up during compiling large projects. They were while loops with logic issues and no clamps - so they could run forever. Mainly found in the code that handled Borland's inline asm blocks.
November got here, and I decided to ask Gemini and Claude, to analyze my compilers capabilities versus Free Pascal, Virtual Pascal, TMT Pascal and the first 3 versions of Delphi. As all of these are minor improvements upon TPC. We did, and the list of changes we ranked from Quick Wins to Months of Work.
Main Requirement, do not deviate from Borland's TP7 file structures.
Ending result? My Blaze Pascal v7.0.2ß - basically improvements to the internal Code Generator, and Optimization Routines.
New Version ~ Blaze Pascal ~ Starting at $135.00
Re: New Version ~ Blaze Pascal ~ Starting at $135.00
===============================================================================
Blaze Pascal - 99% Turbo Pascal 7 compatible compiler WHATSNEW.TXT
Version 7.0.2ß - November 2026
===============================================================================
Blaze Pascal still compiles Turbo Pascal 7 source and still produces the same 16-bit
DOS/Windows executables and units. Everything new in this release is either switched
OFF by default, or uses syntax that Turbo Pascal 7 would reject, so an existing TP7
program compiles exactly as before!
Contents
1. New language features at a glance
2. Compiler switches - complete reference
3. Compiler directives - complete reference
4. Compile-time macros {$I %NAME%}
5. Delphi 2/3, TMT Pascal and Virtual Pascal compatibility
6. Bug fixes in this release
7. Notes for building Blaze Pascal itself
8. Planned
===============================================================================
1. NEW LANGUAGE FEATURES AT A GLANCE
===============================================================================
Feature Enabled by Default Example
------------------------------ ------------------ ---------- ---------------------
Result inside functions {$X+} ON Result := N * 2;
Exit with a return value {$C+} off Exit (-1);
Read-only typed constants {$J-} writable {$J-} Const K: Word=1;
C operators += -= *= /= {$H+} off Total += Price;
TMT operators +:= -:= *:= /:= {$H+} off Total +:= Price;
Ada comments -- text {$AC+} off -- note
{$IF} {$ELSEIF} {$IFEND} {$U+} off {$IF Version >= 3}
Binary literals always - Mask := %10100001;
Octal literals always - Mode := &755;
{$MESSAGE} {$NOTE} {$HINT} always - {$NOTE Beta build}
{$WARNING} {$ERROR} {$FATAL} always - {$ERROR 'Need DPMI'}
{$INCLUDE file} always - {$INCLUDE DEFS.INC}
Compile-time date/time/file always - {$I %DATE%}
Delphi type names (Cardinal...) always - Var W: Cardinal;
MemD (TMT name for MemL) always - W := MemD [$40:$6C];
out parameters always - Procedure P (out X: Integer);
resourcestring sections always - resourcestring SOk = 'OK';
initialization / finalization always - see section 5
Several switches can be combined in one directive, e.g. {$C+,H+,U+}.
Assigned (P) needs no switch: it is a standard Turbo Pascal 7 function.
===============================================================================
2. COMPILER SWITCHES - COMPLETE REFERENCE
===============================================================================
How switches work
-----------------
A switch is a letter followed by + (on) or - (off):
{$R+} in source code
/$R+ on the command line
{$R+,Q+,S-} several at once
GLOBAL switches affect the whole module (program or unit) and must appear
before the first declaration, i.e. before the end of the module heading /
uses clause. They are marked [global] below. All other switches are LOCAL:
they can be turned on and off anywhere, even around a single statement.
{$IFOPT X+} ... {$ENDIF} tests the current state of any switch below.
The defaults shown are what Blaze Pascal (no parameters) lists on its help screen.
A *.CFG file or /$ options on the command line can change them.
$D, $K, $L, $W and $Y are not listed on the help screen; their defaults below
are the Turbo Pascal 7 defaults.
---------------------------------------------------------------------------
$A± Word alignment default A+ [global]
---------------------------------------------------------------------------
A+ aligns variables and typed constants larger than one byte on even (word)
addresses. 8086/80286 CPUs read a word in one bus cycle only when it is at
an even address, so A+ makes code faster at the cost of a few padding bytes.
A- packs data byte-by-byte (smallest size). Record fields are not affected;
use "packed record" for those.
---------------------------------------------------------------------------
$AC± Ada-style comments NEW in 7.0.2ß default AC-
---------------------------------------------------------------------------
The TMT Pascal switch. With AC+, two minus signs start a comment that runs
to the end of the line, as in Ada and TMT Pascal:
{$AC+}
Total := Total + Tax; -- tax was added in version 2
With AC- (the default), -- keeps its Turbo Pascal meaning (minus minus),
so X := Y--1 still compiles. Written with a space, as Y - -1, it is an
expression in both modes.
{$IFOPT AC+} works. Like the other new switches it is local.
---------------------------------------------------------------------------
$B± Complete boolean evaluation default B-
---------------------------------------------------------------------------
B- (short-circuit): evaluation of "and"/"or" stops as soon as the result is
known. If (P <> nil) and (P^.Count > 0) is safe because P^ is never read
when P is nil.
B+ always evaluates every operand, so functions with side effects in a
boolean expression are always called. Rarely needed.
---------------------------------------------------------------------------
$C± C-style Exit (value) NEW in 7.0.2ß default C-
---------------------------------------------------------------------------
With C+, Exit can carry the function result, like "return x" in C or
Exit(x) in Free Pascal and Delphi 2009+:
{$C+}
Function Sign (N: Integer): Integer;
begin
If N < 0 then Exit (-1);
If N = 0 then Exit (0);
Exit (1);
end;
Exit (Value) assigns Value to the function result and leaves the function
immediately. The value is type- and range-checked exactly like an
assignment "Result := Value". It works with every result type (ordinal,
real, string, pointer), inside loops, case and nested blocks.
- Plain "Exit;" is unchanged in every mode.
- Exit (x) inside a procedure gives Error 143 (Invalid procedure or
function reference).
- With C- the old Turbo Pascal meaning is kept and Exit (x) is an error.
- The Borland Pascal 7 form {$C MOVEABLE PRELOAD DISCARDABLE} (code
segment attributes for Windows/DPMI) still works: if the character after
C is not + or -, the directive is treated the TP7 way.
- Note: on the command line /$C is ignored, because the Delphi IDE passes
its own -$C+ (assertions) when it calls Blaze Pascal.
---------------------------------------------------------------------------
$D± Debug information default D+ [global]
---------------------------------------------------------------------------
D+ records line-number information in the unit (.TPU) so that run-time
errors can be located with /F<seg>:<ofs> (Find error). It does not make
the executable larger or slower; Blaze Pascal does not write debug info
into EXE files.
---------------------------------------------------------------------------
$E± 80x87 emulation default E- [global]
---------------------------------------------------------------------------
With N+, E+ links the software floating-point emulator, so programs using
Single/Double/Extended/Comp run on machines without a math co-processor.
E- requires a real 8087/80287/80387 (or a 486DX and later).
---------------------------------------------------------------------------
$F± Force FAR calls default F-
---------------------------------------------------------------------------
F+ compiles every procedure and function with the FAR call model. Needed
for procedures assigned to procedural variables, exit procedures, and
overlaid code. F- lets the compiler choose: NEAR for routines that are
only used inside their unit, FAR for routines in a unit's interface.
Individual routines can still be marked with the "far" directive.
---------------------------------------------------------------------------
$G± 80286 instructions default G+ [global]
---------------------------------------------------------------------------
G+ lets the code generator use 80286 instructions (PUSH immediate, ENTER/
LEAVE, shifts by an immediate count, ...), giving smaller and faster code.
The program then needs at least an 80286. G- generates 8086 code that
runs on any PC.
---------------------------------------------------------------------------
$H C operators += -= *= /= NEW in 7.0.2ß default H-
---------------------------------------------------------------------------
With H+, the C-style compound assignment operators are available (the same
as Free Pascal's {$COPERATORS ON}):
{$H+}
Total += Price; { Total := Total + Price }
Count -= 1; { Count := Count - 1 }
Area *= 2; { Area := Area * 2 }
Ratio /= 3; { Ratio := Ratio / 3 (real types only) }
Name += '.PAS'; { string concatenation works too }
The TMT Pascal spelling of the same operators also works with H+:
Total +:= Price; Count -:= 1; Area *:= 2; Ratio /:= 3;
"V op= E" means exactly "V := V op (E)": the whole right side is evaluated
first, so X *= A + B is X := X * (A + B). Type and range checks are the
same as for a normal assignment, so /= on an integer variable is a type
mismatch, just as I := I / 2 would be.
Note: the address of V is computed twice, so in A [F (X)] += 1 the
function F is called twice. Keep side effects out of the variable part.
With H- the character pairs are read as two separate tokens (TP7 meaning).
Delphi's {$H+} (long strings) in shared source simply enables these
operators, which is harmless. On the command line /$H is ignored.
---------------------------------------------------------------------------
$I I/O checking default I+
---------------------------------------------------------------------------
I+ checks the result of every I/O call (Reset, Rewrite, Read, Write, ...)
and stops the program with a run-time error if it failed. With I- no
check is made; call IOResult after the operation to get (and clear) the
error code:
{$I-} Reset (F); {$I+}
If IOResult <> 0 then Writeln ('File not found');
($I followed by a file name is the Include directive - see section 3.)
---------------------------------------------------------------------------
$J Writable typed constants NEW in 7.0.2ß default J+
---------------------------------------------------------------------------
A typed constant (Const Count: Integer = 0;) is really an initialized
variable. Turbo Pascal 7 always allows assigning to it; that is J+, the
default, so TP7 code is unaffected.
With J- (as in Delphi), typed constants declared while J- is active are
read-only. Reading them works; changing them gives
Error 122 (Invalid variable reference):
{$J-}
Const Limit: Integer = 10;
...
Limit := 5; { Error 122 }
Inc (Limit); { Error 122 }
The state is recorded per constant when it is declared, so {$J-} and {$J+}
can be mixed around individual const sections.
On the command line /$J is ignored (the Delphi IDE always passes -$J-).
---------------------------------------------------------------------------
$K Smart callbacks (Borland Pascal for Windows) default K- [global]
---------------------------------------------------------------------------
Accepted for compatibility with Borland Pascal 7 Windows sources. Only
meaningful for Windows targets; it has no effect on DOS programs.
---------------------------------------------------------------------------
$L Local symbol information default L+ [global]
---------------------------------------------------------------------------
With D+, L+ also records information about local variables and constants
for debuggers. (Also: {$L file.OBJ} links an object file - see section 3.)
---------------------------------------------------------------------------
$N 80x87 numeric processing default N+ [global]
---------------------------------------------------------------------------
N+ makes Real arithmetic and the Single, Double, Extended and Comp types
use 80x87 floating-point code (hardware or emulated, see $E). N- uses the
6-byte software Real only; Single/Double/Extended/Comp are not available.
---------------------------------------------------------------------------
$O Overlays allowed default O+ [global]
---------------------------------------------------------------------------
O+ generates code that is safe to place in a DOS overlay (needed for units
that will be overlaid). {$O UnitName} in the main program marks a unit to be
overlaid. Has nothing to do with optimization - see section 7.
---------------------------------------------------------------------------
$P Open string parameters default P+
---------------------------------------------------------------------------
P+ treats every "var S: String" parameter as an open string, so strings of
any declared length (String[20], String[80], ...) can be passed. P- requires
the exact string type unless $V- is used.
---------------------------------------------------------------------------
$Q Overflow checking default Q-
---------------------------------------------------------------------------
Q+ adds checks after integer +, -, *, Succ, Pred, Inc and Dec so that an
arithmetic overflow stops the program with run-time error 215 instead of
silently wrapping around. Slightly larger and slower code.
---------------------------------------------------------------------------
$R Range checking default R-
---------------------------------------------------------------------------
R+ checks array indexes, string indexes and assignments to subrange and
enumerated variables at run time (run-time error 201). Recommended while
developing; turn off for release builds if speed matters.
---------------------------------------------------------------------------
$S Stack-overflow checking default S-
---------------------------------------------------------------------------
S+ checks on entry to every procedure that enough stack space is left
(run-time error 202). Useful with deep recursion; the stack size is set
with {$M}.
---------------------------------------------------------------------------
$T Typed @ operator default T- [global]
---------------------------------------------------------------------------
T- : @X has the generic type Pointer (TP7 behaviour).
T+ : @X has the type ^T where T is the type of X, so mistakes such as
assigning the address of an Integer to a ^Real are caught.
---------------------------------------------------------------------------
$U Extended conditionals {$IF} NEW in 7.0.2ß default U-
---------------------------------------------------------------------------
With U+, the Free Pascal / Delphi conditional directives are available:
{$U+}
{$IF Defined (DPMI) and (BufferSize >= 4096)}
...
{$ELSEIF Declared (OldApi)}
...
{$ELSE}
...
{$IFEND} { {$ENDIF} is also accepted }
Expressions may use:
Values integer constants 12 $FF %1010 &17
string constants 'Ozz Nixon'
TRUE, FALSE
constants declared in the program or its units (ordinal,
Boolean, Char, enumerated and string constants)
Functions Defined (X) True if X was defined with {$DEFINE X} or /D
Undefined (X) the opposite
Declared (X) True if identifier X is declared (any kind)
Operators NOT unary - * DIV MOD SHL SHR AND
+ - OR XOR = <> < > <= >= ( )
(normal Pascal precedence; AND/OR/XOR/NOT are logical on
Boolean values and bitwise on integers; + joins strings)
An identifier that is not a known constant evaluates to 0.
{$IF} blocks nest freely with {$IFDEF}/{$IFNDEF}/{$IFOPT}. Skipped blocks are
not evaluated. {$ELSEIF} may be repeated; the first true branch is compiled.
With U- the directives give Error 17 (Invalid compiler directive), but {$IF}
blocks inside skipped {$IFDEF} sections are always nested correctly, so
source shared with FPC/Delphi compiles either way.
On the command line /$U is ignored (Delphi passes -$U-).
---------------------------------------------------------------------------
$V Var-string checking default V+
---------------------------------------------------------------------------
V+ (strict): a string passed to a var parameter must have exactly the same
declared length as the parameter. V- (relaxed) allows any string type.
---------------------------------------------------------------------------
$W Windows stack frames (Borland Pascal Windows) default W-
---------------------------------------------------------------------------
Accepted for compatibility with Borland Pascal 7 Windows sources. No
effect on DOS programs.
---------------------------------------------------------------------------
$X Extended syntax default X+ [global]
---------------------------------------------------------------------------
X+ enables the Turbo Pascal 7 extended syntax:
- functions can be called as statements, ignoring the result;
- PChar and zero-based character arrays act as null-terminated strings;
and, new in 7.0.2ß:
- Result: inside a function, Result is the function's return value. It can
be assigned AND read, unlike the function name (reading the name calls
the function recursively):
Function Sum (Const A: Array of Integer): Integer;
Var I: Integer;
begin
Result := 0;
For I := 0 to High (A) do Result := Result + A ;
end;
A variable you declare yourself called Result takes priority, so old code
using that name still works.
---------------------------------------------------------------------------
$Y Symbol reference information default Y+ [global]
---------------------------------------------------------------------------
With D+ and L+, Y+ records where every identifier is declared and used, for
browsers and IDEs.
---------------------------------------------------------------------------
$Z (reserved) default Z-
---------------------------------------------------------------------------
Reserved for a future Blaze Pascal feature. {$Z+} and {$Z-} are accepted and
currently have no effect. The Delphi / Virtual Pascal enumeration-size
forms {$Z1}, {$Z2} and {$Z4} are also accepted and currently ignored
(enumerations stay one byte when they fit, as in Turbo Pascal 7).
Spare switches: the letter Z is reserved for a future feature. The switch set
still has room for 6 more switches (with two-letter names like $AC) before
the .TPU layout would change.
===============================================================================
3. COMPILER DIRECTIVES - COMPLETE REFERENCE
===============================================================================
Conditional compilation
{$DEFINE name} {$UNDEF name} define / remove a symbol
{$IFDEF name} {$IFNDEF name} test a symbol
{$IFOPT X+} test a switch state
{$IF expr} {$ELSEIF expr} {$IFEND} NEW, needs {$U+} (see $U)
{$ELSE} {$ENDIF}
Predefined symbols: MSDOS, VER70, CPU86 and CPU87 (as in TP7), TPC32
(so source can test for this compiler), plus anything given with /D command line.
Files
{$I filename} include a source file (default extension .PAS)
{$INCLUDE filename} NEW: long form of {$I filename}
{$I %NAME%} NEW: compile-time macro - see section 4
{$L filename} link an .OBJ file (external procedures)
{$R filename} accepted and ignored (resources are not linked)
Memory and overlays
{$M stack, heapmin, heapmax} stack and heap sizes of the program
{$O UnitName} overlay a unit (main program only)
Messages NEW
{$MESSAGE 'text'} prints FILE.PAS(12) Info: text
{$MESSAGE HINT 'text'} same with Hint / WARN / ERROR / FATAL / NOTE
{$NOTE text} prints FILE.PAS(12) Note: text
{$HINT text} prints FILE.PAS(12) Hint: text
{$WARNING text} prints FILE.PAS(12) Warning: text
{$ERROR text} stops compilation with
{$FATAL text} Error 171: User defined error (text).
The text can be written plain or in quotes. Typical use:
{$IFNDEF DPMI}
{$ERROR 'This unit needs the DPMI target'}
{$ENDIF}
Compatibility
{$APPTYPE CONSOLE} accepted and ignored (Delphi source)
// line comments and /* block comments */ are accepted
"double-quoted" strings are accepted like 'single-quoted' strings
===============================================================================
4. COMPILE-TIME MACROS {$I %NAME%}
===============================================================================
As in Free Pascal, {$I %NAME%} is replaced by a string constant when the
source is compiled:
{$I %DATE%} '2026/11/09' date of compilation (YYYY/MM/DD)
{$I %TIME%} '14:05:33' time of compilation (HH:MM:SS)
{$I %FILE%} 'MYPROG.PAS' name of the current source file
{$I %LINE%} '42' current line number (as a string)
{$I %NAME%} value of environment variable NAME, or '' if not set
e.g. {$I %USERNAME%}, {$I %COMPUTERNAME%}
Example:
Const BuildStamp = 'Built ' + {$I %DATE%} + ' ' + {$I %TIME%};
begin
Writeln ('MyProg 1.0 Copyright (c) 2026 ', BuildStamp);
end.
Both comment styles work: {$I %DATE%} and (*$I %DATE%*).
The macro is expanded in place in the current source line, so the line
(after expansion) must still fit in 127 characters.
===============================================================================
5. DELPHI 2/3, TMT PASCAL AND VIRTUAL PASCAL COMPATIBILITY
===============================================================================
These help Delphi-style source compile with 7.0.2ß. None of them needs a
switch: each is either a word Turbo Pascal 7 does not know, or it is used
only where a TP7 program could not contain it.
Type names
----------
Cardinal = Word (16-bit unsigned, 0..65535 - as in Delphi 1)
SmallInt = Integer (16-bit signed)
ShortString = String (255 characters)
AnsiChar = Char
PAnsiChar = PChar
These are the same types, not new ones: a variable declared as Cardinal is
stored in the unit as System's Word, so the .TPU format is unchanged and
units stay compatible. If a program or unit declares its own type with one
of these names, that declaration is used instead.
TMT Pascal name:
MemD [Seg:Ofs] = MemL [Seg:Ofs] (32-bit memory access)
Virtual Pascal name:
SmallWord = Word
Note: Delphi 2 and later made Cardinal a 32-bit unsigned type. 7.0.2ß has no
32-bit unsigned arithmetic (Turbo Pascal 7 never had it), so Cardinal follows
the 16-bit Delphi 1 meaning. Use LongInt for larger values.
out parameters
--------------
Procedure GetSize (out Width, Height: Integer);
"out" is treated as "var": the argument is passed by reference and the
procedure sets it. (In Delphi, out only adds that the value going in is
ignored, which makes no difference for 7.0.2ß's types.)
A parameter that is itself called Out (Procedure P (Out: Integer)) still
works: "out" is only a modifier when a parameter name follows it.
resourcestring sections
-----------------------
resourcestring
SFileNotFound = 'File not found';
SDone = 'Done.';
Compiled exactly like a const section of string constants. (DOS programs
have no resources to put them in; this simply lets Delphi source compile.)
initialization / finalization
-----------------------------
A unit can now end in the Delphi way:
unit Logger;
interface
Procedure Log (Const S: String);
implementation
Var LogFile: Text;
Procedure Log (Const S: String); begin Writeln (LogFile, S) end;
initialization
Assign (LogFile, 'APP.LOG');
Rewrite (LogFile);
finalization
Close (LogFile);
end.
Allowed endings of a unit:
begin ... end. (Standard Turbo Pascal 7)
end. (no initialization)
initialization ... end.
initialization ... finalization ... end.
finalization ... end.
- initialization is the same as the unit's begin.
- finalization statements run when the program ends (normally, through
Halt, or after a run-time error), in REVERSE order of the units'
initialization - the same order Delphi uses.
- They are compiled as a hidden far procedure that the unit's initialization
installs in the ExitProc chain, exactly the way TP7 programmers install
exit procedures by hand:
__TPC32Exit := ExitProc; ExitProc := @__TPC32Fin;
and which restores ExitProc first when it runs. Hand-written exit
procedures in other units keep working and chain correctly.
- The finalization section can use everything declared in the unit's
interface and implementation sections. Errors in it are reported with
the correct file name and line number.
- The unit's final "end." must be on one line ("end" and "." together).
- In a program, initialization/finalization are not allowed (as in Delphi).
Virtual Pascal / Delphi extras
------------------------------
threadvar A threadvar section is compiled as a normal var section
(DOS programs have only one thread):
threadvar Counter: Integer;
pascal The calling-convention directive "pascal" is accepted and
ignored, because it is Turbo Pascal's own convention:
Procedure Draw (X, Y: Integer); far; pascal;
cdecl and stdcall are NOT accepted - they would need a
different parameter order and stack cleanup.
uses ... in A unit's source file can be named in the uses clause:
uses Config in 'SHARED\CONFIG.PAS', Crt;
The given file is used whenever 7.0.2ß looks for the unit's
source (with /M, /B, or when no .TPU exists). The .TPU is
still found by the unit name in the EXE/TPU directories.
{&directive} Virtual Pascal's own directives start with & and are plain
comments to TPC32, so VP sources compile unchanged.
===============================================================================
6. BUG FIXES IN THIS RELEASE
===============================================================================
- Any compile error made the compiler crash with an Access Violation
instead of printing the error. The error-recovery code jumped back with
saved CPU registers but did not restore the stack and skipped Delphi's
exception frames. Errors are now handled with a proper exception.
- Code generation did not return from intermediate-code subroutines
(GoSub/Return), which could produce wrong code for WITH statements and
expressions, and wrong ES:DI reload optimization.
- The inline assembler's expression stack had been disabled, corrupting the
stack for operands like [BX].TRec.Field, WORD PTR x, and constant
expressions in ASM blocks.
- Reading Result in an expression (Result := Result + 1) compiled as a
recursive call of the function.
- Profiler (PROFILE build) line numbers corrected throughout, and the log is
now also written when compilation stops on an error.
===============================================================================
7. NOTES FOR BUILDING TPC32 ITSELF
===============================================================================
- Regression tests: run TESTS\RUNTESTS.BAT after every change. It compiles
the test programs with TPC32, runs them in DOSBox-X, compares the output
with the expected results and reports PASS/FAIL (exit code = number of
failures). See TESTS\README.TXT for how to add tests.
- Delphi 7: dcc32 TPC32 /B (dcc32.cfg must contain -$J+)
Profiling build: dcc32 TPC32 /B -DPROFILE (writes PROFILED.LOG)
- Free Pascal: 32-bit and 64-bit targets; CPU-specific code is guarded with
{$IFDEF CPUX64} / {$IFDEF FPC}.
- The start-up banner shows the build date and time of TPC32.EXE.
===============================================================================
8. PLANNED
===============================================================================
- {$OPT+} / {$OPT-}: optional code optimizations (peephole, jump threading,
register tracking), off by default so output stays identical to TP7.
{$O} cannot be used because it controls DOS overlays.
- {$IFOPT OPT+} will work once {$OPT} exists. {$IFOPT} currently reads a
single switch letter, so it will be extended to accept the name OPT.
===============================================================================
Blaze Pascal - 99% Turbo Pascal 7 compatible compiler WHATSNEW.TXT
Version 7.0.2ß - November 2026
===============================================================================
Blaze Pascal still compiles Turbo Pascal 7 source and still produces the same 16-bit
DOS/Windows executables and units. Everything new in this release is either switched
OFF by default, or uses syntax that Turbo Pascal 7 would reject, so an existing TP7
program compiles exactly as before!
Contents
1. New language features at a glance
2. Compiler switches - complete reference
3. Compiler directives - complete reference
4. Compile-time macros {$I %NAME%}
5. Delphi 2/3, TMT Pascal and Virtual Pascal compatibility
6. Bug fixes in this release
7. Notes for building Blaze Pascal itself
8. Planned
===============================================================================
1. NEW LANGUAGE FEATURES AT A GLANCE
===============================================================================
- (C) 2026 by Brain Patchwork DX, LLC.
- Screenshot 2026-11-09 210500.png (44.61 KiB) Viewed 25266 times
------------------------------ ------------------ ---------- ---------------------
Result inside functions {$X+} ON Result := N * 2;
Exit with a return value {$C+} off Exit (-1);
Read-only typed constants {$J-} writable {$J-} Const K: Word=1;
C operators += -= *= /= {$H+} off Total += Price;
TMT operators +:= -:= *:= /:= {$H+} off Total +:= Price;
Ada comments -- text {$AC+} off -- note
{$IF} {$ELSEIF} {$IFEND} {$U+} off {$IF Version >= 3}
Binary literals always - Mask := %10100001;
Octal literals always - Mode := &755;
{$MESSAGE} {$NOTE} {$HINT} always - {$NOTE Beta build}
{$WARNING} {$ERROR} {$FATAL} always - {$ERROR 'Need DPMI'}
{$INCLUDE file} always - {$INCLUDE DEFS.INC}
Compile-time date/time/file always - {$I %DATE%}
Delphi type names (Cardinal...) always - Var W: Cardinal;
MemD (TMT name for MemL) always - W := MemD [$40:$6C];
out parameters always - Procedure P (out X: Integer);
resourcestring sections always - resourcestring SOk = 'OK';
initialization / finalization always - see section 5
Several switches can be combined in one directive, e.g. {$C+,H+,U+}.
Assigned (P) needs no switch: it is a standard Turbo Pascal 7 function.
===============================================================================
2. COMPILER SWITCHES - COMPLETE REFERENCE
===============================================================================
How switches work
-----------------
A switch is a letter followed by + (on) or - (off):
{$R+} in source code
/$R+ on the command line
{$R+,Q+,S-} several at once
GLOBAL switches affect the whole module (program or unit) and must appear
before the first declaration, i.e. before the end of the module heading /
uses clause. They are marked [global] below. All other switches are LOCAL:
they can be turned on and off anywhere, even around a single statement.
{$IFOPT X+} ... {$ENDIF} tests the current state of any switch below.
The defaults shown are what Blaze Pascal (no parameters) lists on its help screen.
A *.CFG file or /$ options on the command line can change them.
$D, $K, $L, $W and $Y are not listed on the help screen; their defaults below
are the Turbo Pascal 7 defaults.
---------------------------------------------------------------------------
$A± Word alignment default A+ [global]
---------------------------------------------------------------------------
A+ aligns variables and typed constants larger than one byte on even (word)
addresses. 8086/80286 CPUs read a word in one bus cycle only when it is at
an even address, so A+ makes code faster at the cost of a few padding bytes.
A- packs data byte-by-byte (smallest size). Record fields are not affected;
use "packed record" for those.
---------------------------------------------------------------------------
$AC± Ada-style comments NEW in 7.0.2ß default AC-
---------------------------------------------------------------------------
The TMT Pascal switch. With AC+, two minus signs start a comment that runs
to the end of the line, as in Ada and TMT Pascal:
{$AC+}
Total := Total + Tax; -- tax was added in version 2
With AC- (the default), -- keeps its Turbo Pascal meaning (minus minus),
so X := Y--1 still compiles. Written with a space, as Y - -1, it is an
expression in both modes.
{$IFOPT AC+} works. Like the other new switches it is local.
---------------------------------------------------------------------------
$B± Complete boolean evaluation default B-
---------------------------------------------------------------------------
B- (short-circuit): evaluation of "and"/"or" stops as soon as the result is
known. If (P <> nil) and (P^.Count > 0) is safe because P^ is never read
when P is nil.
B+ always evaluates every operand, so functions with side effects in a
boolean expression are always called. Rarely needed.
---------------------------------------------------------------------------
$C± C-style Exit (value) NEW in 7.0.2ß default C-
---------------------------------------------------------------------------
With C+, Exit can carry the function result, like "return x" in C or
Exit(x) in Free Pascal and Delphi 2009+:
{$C+}
Function Sign (N: Integer): Integer;
begin
If N < 0 then Exit (-1);
If N = 0 then Exit (0);
Exit (1);
end;
Exit (Value) assigns Value to the function result and leaves the function
immediately. The value is type- and range-checked exactly like an
assignment "Result := Value". It works with every result type (ordinal,
real, string, pointer), inside loops, case and nested blocks.
- Plain "Exit;" is unchanged in every mode.
- Exit (x) inside a procedure gives Error 143 (Invalid procedure or
function reference).
- With C- the old Turbo Pascal meaning is kept and Exit (x) is an error.
- The Borland Pascal 7 form {$C MOVEABLE PRELOAD DISCARDABLE} (code
segment attributes for Windows/DPMI) still works: if the character after
C is not + or -, the directive is treated the TP7 way.
- Note: on the command line /$C is ignored, because the Delphi IDE passes
its own -$C+ (assertions) when it calls Blaze Pascal.
---------------------------------------------------------------------------
$D± Debug information default D+ [global]
---------------------------------------------------------------------------
D+ records line-number information in the unit (.TPU) so that run-time
errors can be located with /F<seg>:<ofs> (Find error). It does not make
the executable larger or slower; Blaze Pascal does not write debug info
into EXE files.
---------------------------------------------------------------------------
$E± 80x87 emulation default E- [global]
---------------------------------------------------------------------------
With N+, E+ links the software floating-point emulator, so programs using
Single/Double/Extended/Comp run on machines without a math co-processor.
E- requires a real 8087/80287/80387 (or a 486DX and later).
---------------------------------------------------------------------------
$F± Force FAR calls default F-
---------------------------------------------------------------------------
F+ compiles every procedure and function with the FAR call model. Needed
for procedures assigned to procedural variables, exit procedures, and
overlaid code. F- lets the compiler choose: NEAR for routines that are
only used inside their unit, FAR for routines in a unit's interface.
Individual routines can still be marked with the "far" directive.
---------------------------------------------------------------------------
$G± 80286 instructions default G+ [global]
---------------------------------------------------------------------------
G+ lets the code generator use 80286 instructions (PUSH immediate, ENTER/
LEAVE, shifts by an immediate count, ...), giving smaller and faster code.
The program then needs at least an 80286. G- generates 8086 code that
runs on any PC.
---------------------------------------------------------------------------
$H C operators += -= *= /= NEW in 7.0.2ß default H-
---------------------------------------------------------------------------
With H+, the C-style compound assignment operators are available (the same
as Free Pascal's {$COPERATORS ON}):
{$H+}
Total += Price; { Total := Total + Price }
Count -= 1; { Count := Count - 1 }
Area *= 2; { Area := Area * 2 }
Ratio /= 3; { Ratio := Ratio / 3 (real types only) }
Name += '.PAS'; { string concatenation works too }
The TMT Pascal spelling of the same operators also works with H+:
Total +:= Price; Count -:= 1; Area *:= 2; Ratio /:= 3;
"V op= E" means exactly "V := V op (E)": the whole right side is evaluated
first, so X *= A + B is X := X * (A + B). Type and range checks are the
same as for a normal assignment, so /= on an integer variable is a type
mismatch, just as I := I / 2 would be.
Note: the address of V is computed twice, so in A [F (X)] += 1 the
function F is called twice. Keep side effects out of the variable part.
With H- the character pairs are read as two separate tokens (TP7 meaning).
Delphi's {$H+} (long strings) in shared source simply enables these
operators, which is harmless. On the command line /$H is ignored.
---------------------------------------------------------------------------
$I I/O checking default I+
---------------------------------------------------------------------------
I+ checks the result of every I/O call (Reset, Rewrite, Read, Write, ...)
and stops the program with a run-time error if it failed. With I- no
check is made; call IOResult after the operation to get (and clear) the
error code:
{$I-} Reset (F); {$I+}
If IOResult <> 0 then Writeln ('File not found');
($I followed by a file name is the Include directive - see section 3.)
---------------------------------------------------------------------------
$J Writable typed constants NEW in 7.0.2ß default J+
---------------------------------------------------------------------------
A typed constant (Const Count: Integer = 0;) is really an initialized
variable. Turbo Pascal 7 always allows assigning to it; that is J+, the
default, so TP7 code is unaffected.
With J- (as in Delphi), typed constants declared while J- is active are
read-only. Reading them works; changing them gives
Error 122 (Invalid variable reference):
{$J-}
Const Limit: Integer = 10;
...
Limit := 5; { Error 122 }
Inc (Limit); { Error 122 }
The state is recorded per constant when it is declared, so {$J-} and {$J+}
can be mixed around individual const sections.
On the command line /$J is ignored (the Delphi IDE always passes -$J-).
---------------------------------------------------------------------------
$K Smart callbacks (Borland Pascal for Windows) default K- [global]
---------------------------------------------------------------------------
Accepted for compatibility with Borland Pascal 7 Windows sources. Only
meaningful for Windows targets; it has no effect on DOS programs.
---------------------------------------------------------------------------
$L Local symbol information default L+ [global]
---------------------------------------------------------------------------
With D+, L+ also records information about local variables and constants
for debuggers. (Also: {$L file.OBJ} links an object file - see section 3.)
---------------------------------------------------------------------------
$N 80x87 numeric processing default N+ [global]
---------------------------------------------------------------------------
N+ makes Real arithmetic and the Single, Double, Extended and Comp types
use 80x87 floating-point code (hardware or emulated, see $E). N- uses the
6-byte software Real only; Single/Double/Extended/Comp are not available.
---------------------------------------------------------------------------
$O Overlays allowed default O+ [global]
---------------------------------------------------------------------------
O+ generates code that is safe to place in a DOS overlay (needed for units
that will be overlaid). {$O UnitName} in the main program marks a unit to be
overlaid. Has nothing to do with optimization - see section 7.
---------------------------------------------------------------------------
$P Open string parameters default P+
---------------------------------------------------------------------------
P+ treats every "var S: String" parameter as an open string, so strings of
any declared length (String[20], String[80], ...) can be passed. P- requires
the exact string type unless $V- is used.
---------------------------------------------------------------------------
$Q Overflow checking default Q-
---------------------------------------------------------------------------
Q+ adds checks after integer +, -, *, Succ, Pred, Inc and Dec so that an
arithmetic overflow stops the program with run-time error 215 instead of
silently wrapping around. Slightly larger and slower code.
---------------------------------------------------------------------------
$R Range checking default R-
---------------------------------------------------------------------------
R+ checks array indexes, string indexes and assignments to subrange and
enumerated variables at run time (run-time error 201). Recommended while
developing; turn off for release builds if speed matters.
---------------------------------------------------------------------------
$S Stack-overflow checking default S-
---------------------------------------------------------------------------
S+ checks on entry to every procedure that enough stack space is left
(run-time error 202). Useful with deep recursion; the stack size is set
with {$M}.
---------------------------------------------------------------------------
$T Typed @ operator default T- [global]
---------------------------------------------------------------------------
T- : @X has the generic type Pointer (TP7 behaviour).
T+ : @X has the type ^T where T is the type of X, so mistakes such as
assigning the address of an Integer to a ^Real are caught.
---------------------------------------------------------------------------
$U Extended conditionals {$IF} NEW in 7.0.2ß default U-
---------------------------------------------------------------------------
With U+, the Free Pascal / Delphi conditional directives are available:
{$U+}
{$IF Defined (DPMI) and (BufferSize >= 4096)}
...
{$ELSEIF Declared (OldApi)}
...
{$ELSE}
...
{$IFEND} { {$ENDIF} is also accepted }
Expressions may use:
Values integer constants 12 $FF %1010 &17
string constants 'Ozz Nixon'
TRUE, FALSE
constants declared in the program or its units (ordinal,
Boolean, Char, enumerated and string constants)
Functions Defined (X) True if X was defined with {$DEFINE X} or /D
Undefined (X) the opposite
Declared (X) True if identifier X is declared (any kind)
Operators NOT unary - * DIV MOD SHL SHR AND
+ - OR XOR = <> < > <= >= ( )
(normal Pascal precedence; AND/OR/XOR/NOT are logical on
Boolean values and bitwise on integers; + joins strings)
An identifier that is not a known constant evaluates to 0.
{$IF} blocks nest freely with {$IFDEF}/{$IFNDEF}/{$IFOPT}. Skipped blocks are
not evaluated. {$ELSEIF} may be repeated; the first true branch is compiled.
With U- the directives give Error 17 (Invalid compiler directive), but {$IF}
blocks inside skipped {$IFDEF} sections are always nested correctly, so
source shared with FPC/Delphi compiles either way.
On the command line /$U is ignored (Delphi passes -$U-).
---------------------------------------------------------------------------
$V Var-string checking default V+
---------------------------------------------------------------------------
V+ (strict): a string passed to a var parameter must have exactly the same
declared length as the parameter. V- (relaxed) allows any string type.
---------------------------------------------------------------------------
$W Windows stack frames (Borland Pascal Windows) default W-
---------------------------------------------------------------------------
Accepted for compatibility with Borland Pascal 7 Windows sources. No
effect on DOS programs.
---------------------------------------------------------------------------
$X Extended syntax default X+ [global]
---------------------------------------------------------------------------
X+ enables the Turbo Pascal 7 extended syntax:
- functions can be called as statements, ignoring the result;
- PChar and zero-based character arrays act as null-terminated strings;
and, new in 7.0.2ß:
- Result: inside a function, Result is the function's return value. It can
be assigned AND read, unlike the function name (reading the name calls
the function recursively):
Function Sum (Const A: Array of Integer): Integer;
Var I: Integer;
begin
Result := 0;
For I := 0 to High (A) do Result := Result + A ;
end;
A variable you declare yourself called Result takes priority, so old code
using that name still works.
---------------------------------------------------------------------------
$Y Symbol reference information default Y+ [global]
---------------------------------------------------------------------------
With D+ and L+, Y+ records where every identifier is declared and used, for
browsers and IDEs.
---------------------------------------------------------------------------
$Z (reserved) default Z-
---------------------------------------------------------------------------
Reserved for a future Blaze Pascal feature. {$Z+} and {$Z-} are accepted and
currently have no effect. The Delphi / Virtual Pascal enumeration-size
forms {$Z1}, {$Z2} and {$Z4} are also accepted and currently ignored
(enumerations stay one byte when they fit, as in Turbo Pascal 7).
Spare switches: the letter Z is reserved for a future feature. The switch set
still has room for 6 more switches (with two-letter names like $AC) before
the .TPU layout would change.
===============================================================================
3. COMPILER DIRECTIVES - COMPLETE REFERENCE
===============================================================================
Conditional compilation
{$DEFINE name} {$UNDEF name} define / remove a symbol
{$IFDEF name} {$IFNDEF name} test a symbol
{$IFOPT X+} test a switch state
{$IF expr} {$ELSEIF expr} {$IFEND} NEW, needs {$U+} (see $U)
{$ELSE} {$ENDIF}
Predefined symbols: MSDOS, VER70, CPU86 and CPU87 (as in TP7), TPC32
(so source can test for this compiler), plus anything given with /D command line.
Files
{$I filename} include a source file (default extension .PAS)
{$INCLUDE filename} NEW: long form of {$I filename}
{$I %NAME%} NEW: compile-time macro - see section 4
{$L filename} link an .OBJ file (external procedures)
{$R filename} accepted and ignored (resources are not linked)
Memory and overlays
{$M stack, heapmin, heapmax} stack and heap sizes of the program
{$O UnitName} overlay a unit (main program only)
Messages NEW
{$MESSAGE 'text'} prints FILE.PAS(12) Info: text
{$MESSAGE HINT 'text'} same with Hint / WARN / ERROR / FATAL / NOTE
{$NOTE text} prints FILE.PAS(12) Note: text
{$HINT text} prints FILE.PAS(12) Hint: text
{$WARNING text} prints FILE.PAS(12) Warning: text
{$ERROR text} stops compilation with
{$FATAL text} Error 171: User defined error (text).
The text can be written plain or in quotes. Typical use:
{$IFNDEF DPMI}
{$ERROR 'This unit needs the DPMI target'}
{$ENDIF}
Compatibility
{$APPTYPE CONSOLE} accepted and ignored (Delphi source)
// line comments and /* block comments */ are accepted
"double-quoted" strings are accepted like 'single-quoted' strings
===============================================================================
4. COMPILE-TIME MACROS {$I %NAME%}
===============================================================================
As in Free Pascal, {$I %NAME%} is replaced by a string constant when the
source is compiled:
{$I %DATE%} '2026/11/09' date of compilation (YYYY/MM/DD)
{$I %TIME%} '14:05:33' time of compilation (HH:MM:SS)
{$I %FILE%} 'MYPROG.PAS' name of the current source file
{$I %LINE%} '42' current line number (as a string)
{$I %NAME%} value of environment variable NAME, or '' if not set
e.g. {$I %USERNAME%}, {$I %COMPUTERNAME%}
Example:
Const BuildStamp = 'Built ' + {$I %DATE%} + ' ' + {$I %TIME%};
begin
Writeln ('MyProg 1.0 Copyright (c) 2026 ', BuildStamp);
end.
Both comment styles work: {$I %DATE%} and (*$I %DATE%*).
The macro is expanded in place in the current source line, so the line
(after expansion) must still fit in 127 characters.
===============================================================================
5. DELPHI 2/3, TMT PASCAL AND VIRTUAL PASCAL COMPATIBILITY
===============================================================================
These help Delphi-style source compile with 7.0.2ß. None of them needs a
switch: each is either a word Turbo Pascal 7 does not know, or it is used
only where a TP7 program could not contain it.
Type names
----------
Cardinal = Word (16-bit unsigned, 0..65535 - as in Delphi 1)
SmallInt = Integer (16-bit signed)
ShortString = String (255 characters)
AnsiChar = Char
PAnsiChar = PChar
These are the same types, not new ones: a variable declared as Cardinal is
stored in the unit as System's Word, so the .TPU format is unchanged and
units stay compatible. If a program or unit declares its own type with one
of these names, that declaration is used instead.
TMT Pascal name:
MemD [Seg:Ofs] = MemL [Seg:Ofs] (32-bit memory access)
Virtual Pascal name:
SmallWord = Word
Note: Delphi 2 and later made Cardinal a 32-bit unsigned type. 7.0.2ß has no
32-bit unsigned arithmetic (Turbo Pascal 7 never had it), so Cardinal follows
the 16-bit Delphi 1 meaning. Use LongInt for larger values.
out parameters
--------------
Procedure GetSize (out Width, Height: Integer);
"out" is treated as "var": the argument is passed by reference and the
procedure sets it. (In Delphi, out only adds that the value going in is
ignored, which makes no difference for 7.0.2ß's types.)
A parameter that is itself called Out (Procedure P (Out: Integer)) still
works: "out" is only a modifier when a parameter name follows it.
resourcestring sections
-----------------------
resourcestring
SFileNotFound = 'File not found';
SDone = 'Done.';
Compiled exactly like a const section of string constants. (DOS programs
have no resources to put them in; this simply lets Delphi source compile.)
initialization / finalization
-----------------------------
A unit can now end in the Delphi way:
unit Logger;
interface
Procedure Log (Const S: String);
implementation
Var LogFile: Text;
Procedure Log (Const S: String); begin Writeln (LogFile, S) end;
initialization
Assign (LogFile, 'APP.LOG');
Rewrite (LogFile);
finalization
Close (LogFile);
end.
Allowed endings of a unit:
begin ... end. (Standard Turbo Pascal 7)
end. (no initialization)
initialization ... end.
initialization ... finalization ... end.
finalization ... end.
- initialization is the same as the unit's begin.
- finalization statements run when the program ends (normally, through
Halt, or after a run-time error), in REVERSE order of the units'
initialization - the same order Delphi uses.
- They are compiled as a hidden far procedure that the unit's initialization
installs in the ExitProc chain, exactly the way TP7 programmers install
exit procedures by hand:
__TPC32Exit := ExitProc; ExitProc := @__TPC32Fin;
and which restores ExitProc first when it runs. Hand-written exit
procedures in other units keep working and chain correctly.
- The finalization section can use everything declared in the unit's
interface and implementation sections. Errors in it are reported with
the correct file name and line number.
- The unit's final "end." must be on one line ("end" and "." together).
- In a program, initialization/finalization are not allowed (as in Delphi).
Virtual Pascal / Delphi extras
------------------------------
threadvar A threadvar section is compiled as a normal var section
(DOS programs have only one thread):
threadvar Counter: Integer;
pascal The calling-convention directive "pascal" is accepted and
ignored, because it is Turbo Pascal's own convention:
Procedure Draw (X, Y: Integer); far; pascal;
cdecl and stdcall are NOT accepted - they would need a
different parameter order and stack cleanup.
uses ... in A unit's source file can be named in the uses clause:
uses Config in 'SHARED\CONFIG.PAS', Crt;
The given file is used whenever 7.0.2ß looks for the unit's
source (with /M, /B, or when no .TPU exists). The .TPU is
still found by the unit name in the EXE/TPU directories.
{&directive} Virtual Pascal's own directives start with & and are plain
comments to TPC32, so VP sources compile unchanged.
===============================================================================
6. BUG FIXES IN THIS RELEASE
===============================================================================
- Any compile error made the compiler crash with an Access Violation
instead of printing the error. The error-recovery code jumped back with
saved CPU registers but did not restore the stack and skipped Delphi's
exception frames. Errors are now handled with a proper exception.
- Code generation did not return from intermediate-code subroutines
(GoSub/Return), which could produce wrong code for WITH statements and
expressions, and wrong ES:DI reload optimization.
- The inline assembler's expression stack had been disabled, corrupting the
stack for operands like [BX].TRec.Field, WORD PTR x, and constant
expressions in ASM blocks.
- Reading Result in an expression (Result := Result + 1) compiled as a
recursive call of the function.
- Profiler (PROFILE build) line numbers corrected throughout, and the log is
now also written when compilation stops on an error.
===============================================================================
7. NOTES FOR BUILDING TPC32 ITSELF
===============================================================================
- Regression tests: run TESTS\RUNTESTS.BAT after every change. It compiles
the test programs with TPC32, runs them in DOSBox-X, compares the output
with the expected results and reports PASS/FAIL (exit code = number of
failures). See TESTS\README.TXT for how to add tests.
- Delphi 7: dcc32 TPC32 /B (dcc32.cfg must contain -$J+)
Profiling build: dcc32 TPC32 /B -DPROFILE (writes PROFILED.LOG)
- Free Pascal: 32-bit and 64-bit targets; CPU-specific code is guarded with
{$IFDEF CPUX64} / {$IFDEF FPC}.
- The start-up banner shows the build date and time of TPC32.EXE.
===============================================================================
8. PLANNED
===============================================================================
- {$OPT+} / {$OPT-}: optional code optimizations (peephole, jump threading,
register tracking), off by default so output stays identical to TP7.
{$O} cannot be used because it controls DOS overlays.
- {$IFOPT OPT+} will work once {$OPT} exists. {$IFOPT} currently reads a
single switch letter, so it will be extended to accept the name OPT.
===============================================================================
Re: New Version ~ Blaze Pascal ~ Starting at $135.00
What does a compile time error look like?
I also built in a better RTE (Rumtime Error Report):
Instead of saying:
Runtime error 123 at 0000:1234.
You get:
Runtime error 123 at 0000:1234 in FILENAME.PAS line 742.
Disclaimer/Requirement:
Line info has to be compiled in. Code built with {$D+} has it, and that’s the default. Units compiled with {$D-}, and Borland TPUs without debug info, just show the address as today.
- (C) 2028 by Brain Patchwork DX, LLC.
- Screenshot 2026-11-09 225644.png (19.64 KiB) Viewed 24869 times
Instead of saying:
Runtime error 123 at 0000:1234.
You get:
Runtime error 123 at 0000:1234 in FILENAME.PAS line 742.
Disclaimer/Requirement:
Line info has to be compiled in. Code built with {$D+} has it, and that’s the default. Units compiled with {$D-}, and Borland TPUs without debug info, just show the address as today.
Re: New Version ~ Blaze Pascal ~ Starting at $135.00
Advanced Code Analysis
I think this is the only compiler that evaluates all variable assignments without costing time.
I think this is the only compiler that evaluates all variable assignments without costing time.
- (C) 2026 by Brain Patchwork DX, LLC.
- Screenshot 2026-11-10 130402.png (26.48 KiB) Viewed 20857 times