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8bitworkshop/presets/astrocade/aclib.s

38 lines
866 B
ArmAsm

.include "astrocade.inc"
;;; C functions
.area _CODE_ACLIB
; set entire palette at once (8 bytes to port 0xb)
; bytes in array should be in reverse
;void set_palette(byte palette[8]) __z88dk_fastcall {
.globl _set_palette
_set_palette:
ld bc,#0x80b ; B -> 8, C -> 0xb
otir ; write C bytes from HL to port[B]
ret
; set entire sound registers at once (8 bytes to port 0x18)
; bytes in array should be in reverse
;void set_sound_registers(byte regs[8]) __z88dk_fastcall {
.globl _set_sound_registers
_set_sound_registers:
ld bc,#0x818 ; B -> 8, C -> 0x18
otir ; write C bytes from HL to port[B]
ret
; set interrupt vector
; pass address of 16-bit pointer to routine
.globl _set_interrupt_vector
_set_interrupt_vector:
di
ld a,l
out (INFBK),a
ld a,h ; upper 8 bits of address
ld i,a ; -> I
im 2 ; mode 2
ei ; enable interrupts
ret