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| author | user <user@clank> | 2026-07-15 23:54:13 +0200 |
|---|---|---|
| committer | user <user@clank> | 2026-07-15 23:54:13 +0200 |
| commit | ab3ebbe227c72b745a46f9233fbfbb27477586b8 (patch) | |
| tree | d71f87605d17c5653f34ebcdef3941f898cd5b91 /src/kdata.asm | |
| parent | gbos scaffold: working cooperative microkernel (verified ABAB in emulator) (diff) | |
| download | gbos-ab3ebbe227c72b745a46f9233fbfbb27477586b8.tar.gz gbos-ab3ebbe227c72b745a46f9233fbfbb27477586b8.tar.xz gbos-ab3ebbe227c72b745a46f9233fbfbb27477586b8.zip | |
kernel: implement fork()
- sys_fork: switch to a kernel stack, bump-allocate a cart-RAM bank, copy the
parent's 8 KiB bank via a WRAM bounce buffer, plant a switch-in frame so the
child returns 0 to the post-fork PC, fill the child PCB (shared ROM text)
- add AllocRamBank (bump allocator) + FindFreeSlot helpers
- demo: init forks; parent prints P, child prints C (PCPC...); nested fork
gives three distinct pids (123...)
- README: document the fork mechanism, mark syscall status
Diffstat (limited to 'src/kdata.asm')
| -rw-r--r-- | src/kdata.asm | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/kdata.asm b/src/kdata.asm index efc780a..ba395f1 100644 --- a/src/kdata.asm +++ b/src/kdata.asm @@ -20,3 +20,14 @@ wTmpWramB:: DS 1 wTmpSlot:: DS 1 wTmpPid:: DS 1 wTmpSP:: DS 2 + +; cart-RAM bank allocator (bump; bank 0 taken by the init task) +wNextRamBank:: DS 1 + +; scratch used by sys_fork +wForkUserSP:: DS 2 ; parent user SP at fork entry (= Uafter) +wForkChildSlot:: DS 1 +wForkChildPid:: DS 1 +wForkParentBank::DS 1 +wForkChildBank:: DS 1 +wCopyBuf:: DS 256 ; bank-copy bounce buffer (WRAM0, always mapped) |