From ab3ebbe227c72b745a46f9233fbfbb27477586b8 Mon Sep 17 00:00:00 2001
From: user <user@clank>
Date: Wed, 15 Jul 2026 23:54:13 +0200
Subject: 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
---
 src/boot.asm | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

(limited to 'src/boot.asm')

diff --git a/src/boot.asm b/src/boot.asm
index 513c392..73ea860 100644
--- a/src/boot.asm
+++ b/src/boot.asm
@@ -50,18 +50,12 @@ KernelInit:
     call CopyHramCode           ; move context-switch trampoline into HRAM
     call ProcInit               ; wipe process table
 
-    ; --- spawn the two demo tasks (text-in-ROM model) ---
-    ; task A: entry TaskA, RAM bank 0, u-area WRAM bank 1
-    ld hl, TaskA
-    ld b, 0                     ; RAM bank
+    ; --- spawn the init task (pid 1); it fork()s the rest ---
+    ld hl, TaskInit
+    ld b, 0                     ; cart-RAM bank 0
     ld c, 1                     ; WRAM u-area bank
     call ProcCreate
 
-    ld hl, TaskB
-    ld b, 1
-    ld c, 2
-    call ProcCreate
-
     call SchedInit              ; pick first task, set wCurProc
 
     ; interrupts: enable timer for preemption
-- 
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