Runtime Library Notes

  sd8516/                  project root
    runtime/
      crt0.sda             startup stub -- CALL main
      librt/               runtime functions
        divhi3.c
        modhi3.c
        divsi3.c
        muldi3.c
        ...
        softfloat/         the SF/DF families
      include/             freestanding headers (mine & what clang supplies)
      tests/               tests with checks

• Helper scripts were created this time: c2sda, c2ll, ll2sda and runtests.
• Next I had to modify VC-4 to take .sda files at the command line (to speed the dev cycle).
• Next I created the above directory.
• I will have to modify vc4 to look in ~/.vc4 if the files it needs are not in the pwd.

Many standard implementations reveal deficiencies in instrinfo and iseltargetlowering.

I collected all the tests into one file.

• putchar.sda (the only assembly only file so far – similar to tinyc v1)
• print_str
• print_dec
• lib1 (stuff for missing instructions)
• libctype
• libstr
• libstdlib

then

• stdint.h, limits.h, stddef.h, stdbool.h
• stdalign/stdnoreturn/iso646
• finish string.h (memchr, strncat, strpbrk, strspn, strcspn, strtok)
• safe-string extras (strlcpy/strlcat, strcasecmp/strncasecmp, memmem),
• div/ldiv, rand/srand, qsort/bsearch, assert.h
• official puts/getchar.

Roadmap which requires additional development:

• malloc/free/calloc/realloc
• then strdup/strndup

Phase III

• stdarg.h for varargs and formatted output. very high value target (enables printf)
• printf/sprintf/snprintf/vsnprintf and sscanf.

Later:

• compiler-facing primitives LEA, MOVSX, CMOV, get CASETAB to emit.
• 64-bit integers. muldi3, udivdi3/umoddi3, divdi3/moddi3.

Floating Point Roadmap:

• Start writing math.h and see what happens.
• strtod/atof, %f for printf.

File IO Roadmap:

• fopen/fread/fwrite/fseek/fclose and FILE* streams wrapping *(see INT 15h/OPFS/FCB)

Other:

• time.h, calendar math, binding time() to the hardware clock

• Graphics and Sound libraries
• access to PPU and ASU

“A growable, chunked, monotonic region allocator.”

This is very similar to the NVAR system I wrote for BASIC. Hanson uses “arena” in C Interfaces and Implementations; the academic literature says “region”. “Bump allocator” is the name of the mechanism, advancing a pointer within a chunk, but the whole structure, with chunked growth and free-everything-at-once teardown, is the arena.