mirror of
https://github.com/sehugg/8bitworkshop.git
synced 2024-12-21 06:29:48 +00:00
108 lines
1.9 KiB
ArmAsm
108 lines
1.9 KiB
ArmAsm
|
|
TEST = 1
|
|
|
|
.module biosasm
|
|
.globl _STIMER,_CTIMER,_BIGFONT,_SMLFONT
|
|
|
|
BIOSStart:
|
|
di ; disable interrupts
|
|
ld HL,#0x2000
|
|
.if TEST
|
|
ld HL,#(_main)
|
|
.endif
|
|
ld A,(HL) ; A <- mem[0x2000]
|
|
cp #0x55 ; found sentinel byte? ($55)
|
|
jp Z,FoundSentinel ; yes, load program
|
|
.if TEST
|
|
jp _main ; jump to test program
|
|
.else
|
|
jp 0x2000 ; jump to $2000
|
|
.endif
|
|
FoundSentinel:
|
|
ld SP,#0x4fce ; position stack below BIOS vars
|
|
call _bios_init ; misc. bios init routines
|
|
.if TEST
|
|
ld HL,#(_main+5)
|
|
.else
|
|
ld HL,#0x2005 ; cartridge start vector
|
|
.endif
|
|
ld A,(HL)
|
|
inc HL
|
|
ld H,(HL)
|
|
ld L,A
|
|
jp (HL) ; jump to cart start vector
|
|
|
|
.ds 0x38 - (. - BIOSStart) ; eat up space until 0x38
|
|
.globl SYSCALL38
|
|
SYSCALL38:
|
|
push hl
|
|
push af
|
|
push bc
|
|
push de
|
|
push ix
|
|
push iy
|
|
ld hl,#0
|
|
add hl,sp
|
|
push hl ; HL points to context block
|
|
call _SYSCALL ; syscall handler
|
|
pop hl
|
|
pop iy
|
|
pop ix
|
|
pop de
|
|
pop bc
|
|
pop af
|
|
pop hl
|
|
ret
|
|
|
|
; out to port
|
|
.globl _portOut
|
|
_portOut:
|
|
ld c,h
|
|
out (c),l
|
|
ret
|
|
|
|
.globl _bcdadd8
|
|
_bcdadd8:
|
|
push ix
|
|
ld ix,#0
|
|
add ix,sp
|
|
ld a,6(ix) ; carry
|
|
rrc a ; set carry bit
|
|
ld h,#0 ; carry goes here
|
|
ld a,4(ix) ; a -> A
|
|
adc a,5(ix) ; a + b -> A
|
|
daa ; BCD conversion
|
|
ld l,a ; result -> L
|
|
rl h ; carry -> H
|
|
pop ix
|
|
ret
|
|
|
|
;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
|
|
|
|
.globl _KCTASC_TABLE
|
|
_KCTASC_TABLE:
|
|
.db 0x00
|
|
.db 0x43, 0x5e, 0x5c, 0x25, 0x52, 0x53, 0x3b, 0x2f
|
|
.db 0x37, 0x38, 0x39, 0x2a, 0x34, 0x35, 0x36, 0x2d
|
|
.db 0x31, 0x32, 0x33, 0x2b, 0x26, 0x30, 0x2e, 0x3d
|
|
|
|
|
|
.ds 0x200 - (. - BIOSStart) ; eat up space until 0x200
|
|
DOPEVector:
|
|
JP _STIMER
|
|
JP _CTIMER
|
|
.db 0x20, 8, 8, 1, 7 ; Font descriptor (big font)
|
|
.dw _BIGFONT
|
|
.db 0xa0, 4, 6, 1, 5 ; Font descriptor (small font)
|
|
.dw _SMLFONT
|
|
.db 0x3f ; all keys mask
|
|
.db 0x3f
|
|
.db 0x3f
|
|
.db 0x3f
|
|
|