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; =============================================================================
; tasks.asm - the init task demonstrates fork().
; init forks once; the parent loops printing 'P', the child loops printing 'C'.
; Both run the same ROM text, diverging on fork()'s return value (0 in child).
; Exercises: syscall trap, fork (8 KiB bank copy + child frame), scheduler,
; and the HRAM context switch swapping cart-RAM banks per task.
; =============================================================================
INCLUDE "include/gbos.inc"
SECTION "tasks", ROM0
TaskInit::
ld c, SYS_FORK
rst $30 ; A = child pid (parent) or 0 (child)
or a
jr z, .child
.parent
ld de, .pmsg
ld b, 1
ld c, SYS_WRITE
rst $30
ld c, SYS_YIELD
rst $30
jr .parent
.child
ld de, .cmsg
ld b, 1
ld c, SYS_WRITE
rst $30
ld c, SYS_YIELD
rst $30
jr .child
.pmsg
db "P"
.cmsg
db "C"
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