gerph Writing Pascal for RISC OS
Use this skill for Pascal work in the RISC OS build environment.
Read only the reference files needed for the task:
- Build, source layout, and command lines (32-bit and 64-bit, direct and
project builds):
references/building.md - Common pitfalls, language quirks, and review checks:
references/pitfalls.md
Core Rules
Pascal source is translated to ANSI C by the P2C translator, then compiled
and linked with the normal C toolchain. riscos-p2cc (32-bit and 26-bit) and
riscos64-p2cc (64-bit) drive translation, compilation, and linking
together.
Pascal source files live in p/. Unlike the C, C++, and Fortran wrappers,
riscos-p2cc takes the host path directly, so pass p/hello, not p.hello
or hello.p.
Always pass -26, -32, or -64 explicitly. Without one, riscos-p2cc
defaults to 26-bit code, which fails at run time with
26 bit absolute files are not executable on this system on a 32-bit or
64-bit system.
The o/ directory must exist before compiling with a 32-bit target, even
for a combined translate-compile-link command; the 32-bit compiler writes an
intermediate object there. The 64-bit compiler does not need this.
Do not print a real value with write/writeln in a 32-bit build.
This currently produces incorrect output (0.0, or garbage for an
unformatted writeln) due to a variadic-double calling-convention bug in
the 32-bit toolchain. real arithmetic and comparisons are unaffected, and
64-bit builds print real values correctly. If a 32-bit program must show a
computed value, convert with trunc/round to an integer, or target 64-bit.
To create a project: riscos-project create --type pcommand --name <name> --skeleton, then riscos-amu for 32-bit or riscos-amu BUILD64=1 for
64-bit.
Assignment is :=, comparison is =. Boolean operators are the words
and, or, not. Array bounds are declared explicitly (eg
array[1..3] of integer), not fixed at a language-defined start index.