4cade/src/macros.a
2020-05-26 14:52:16 -07:00

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;license:MIT
;(c) 2018-2020 by 4am
;
; common assembler macros (6502 compatible)
;
; for functions that take parameters on the stack
; set (PARAM) to point to the parameters and
; move the stack pointer to the first byte after the parameters
; clobbers A,X,Y
!macro PARAMS_ON_STACK .bytes {
pla
sta PARAM
clc
adc #.bytes
tay
pla
sta PARAM+1
adc #0
pha
tya
pha
}
; for functions that take parameters on the stack
; load a 16-bit value from the parameters on the stack into A (low) and Y (high)
; (assumes PARAMS_ON_STACK was used first)
!macro LDPARAM .offset {
ldy #.offset
lda (PARAM),y
pha
iny
lda (PARAM),y
tay
pla
}
; for functions that take parameters on the stack
; load a 16-bit value from the parameters on the stack into A (low) and Y (high)
; then store it as new source
; (assumes PARAMS_ON_STACK was used first)
!macro LDPARAMPTR .offset,.dest {
ldy #.offset
lda (PARAM),y
sta .dest
iny
lda (PARAM),y
sta .dest+1
}
; load the address of .ptr into A (low) and Y (high)
!macro LDADDR .ptr {
lda #<.ptr
ldy #>.ptr
}
; load a 16-bit value into A (low) and Y (high)
!macro LD16 .ptr {
lda .ptr
ldy .ptr+1
}
; store a 16-bit value from A (low) and Y (high)
!macro ST16 .ptr {
sta .ptr
sty .ptr+1
}
; decrement a 16-bit value in A (low) and Y (high)
!macro DEC16 {
sec
sbc #1
bcs +
dey
+
}
; increment a 16-bit value in A (low) and Y (high)
!macro INC16 {
clc
adc #1
bne +
iny
+
}
; compare a 16-bit value in A (low) and Y (high) to an absolute address
!macro CMP16ADDR .addr {
cmp .addr
bne +
cpy .addr+1
+
}
; compare a 16-bit value in A (low) and Y (high) to an immediate value
!macro CMP16 .val {
cmp #<.val
bne +
cpy #>.val
+
}
!macro LBPL .target {
bmi +
jmp .target
+
}
!macro LBNE .target {
beq +
jmp .target
+
}
!macro LBCS .target {
bcc +
jmp .target
+
}
; use BIT to swallow the following 1-byte opcode
!macro HIDE_NEXT_BYTE {
!byte $24
}
; use BIT to swallow the following 2-byte opcode
!macro HIDE_NEXT_2_BYTES {
!byte $2C
}
; debugging
!macro DEBUGWAIT {
bit $c010
- bit $c000
bpl -
bit $c010
}
; various language card configurations
!macro READ_RAM1_NO_WRITE {
bit $C088
}
!macro READ_RAM1_WRITE_RAM1 {
bit $C08B
bit $C08B
}
!macro READ_RAM2_NO_WRITE {
bit $C080
}
!macro READ_RAM2_WRITE_RAM2 {
bit $C083
bit $C083
}
!macro READ_ROM_WRITE_RAM1 {
bit $C089
bit $C089
}
!macro READ_ROM_WRITE_RAM2 {
bit $C081
bit $C081
}
!macro READ_ROM_NO_WRITE {
bit $C082
}
!macro LOW_ASCII_TO_LOWER {
cmp #$41
bcc +
cmp #$5B
bcs +
ora #$20
+
}
; requires setting zpCharMask in zero page to #$FF or #$DF before use
!macro FORCE_UPPERCASE_IF_REQUIRED {
cmp #$E1
bcc +
and zpCharMask
+
}
!macro HGR_BYTE_TO_DHGR_BYTES {
;1GFEDCBA ->
;1GGFFEED (main) +
;1DCCBBAA (aux)
;
; in: A = HGR byte
; out: A = DHGR byte in mainmem
; X = DHGR byte in auxmem
; preserves Y
; clobbers zero page $00,$01,$02
sty $02
ldy #$02
-- stx $01
ldx #$04
- ror $00 ; duplicate previous bit
lsr ; fetch bit
php
ror $00 ; insert bit
plp
dex
bne -
ldx $00
dey
bne --
txa
sec
ror $01 ; set bit 7 explicitly on auxmem value
ldx $01
ldy $02
}
; these are mostly for prelaunchers -- code in the main program should keep track of which bank is active to minimize code size
!macro ENABLE_ACCEL {
+READ_RAM2_NO_WRITE
jsr EnableAccelerator
+READ_ROM_NO_WRITE
}
!macro DISABLE_ACCEL {
+READ_RAM2_NO_WRITE
jsr DisableAccelerator
+READ_ROM_NO_WRITE
}
!macro GET_MACHINE_STATUS {
+READ_RAM2_NO_WRITE
lda MachineStatus
+READ_ROM_NO_WRITE
}
!macro GET_MOCKINGBOARD_SPEECH { ;carry set if present
+READ_RAM2_NO_WRITE
lda MockingboardStuff
asl
+READ_ROM_NO_WRITE
}
!macro GET_MOCKINGBOARD_SPEECH_AND_MACHINE_STATUS { ;carry set if present
+READ_RAM2_NO_WRITE
lda MockingboardStuff
asl
lda MachineStatus
+READ_ROM_NO_WRITE
}
!macro GET_MOCKINGBOARD_SLOT { ;carry set if present
+READ_RAM2_NO_WRITE
lda MockingboardStuff
cmp #1
ora #$C0
+READ_ROM_NO_WRITE
}
!macro GET_MOCKINGBOARD_SLOT_AND_MACHINE_STATUS { ;carry set if present
+READ_RAM2_NO_WRITE
lda MockingboardStuff
cmp #1
ora #$C0
tax
lda MachineStatus
+READ_ROM_NO_WRITE
}
!macro USES_TEXT_PAGE_2 {
lda ROM_MACHINEID
cmp #$06
bne +
sec
jsr $FE1F ; check for IIgs
bcs +
jsr ROM_TEXT2COPY ; set alternate display mode on IIgs (required for some games)
+
}
!macro RESET_VECTOR .addr {
lda #<.addr
sta $3F2
lda #>.addr
sta $3F3
eor #$A5
sta $3F4
}
; for games that clobber $100-$105, the prelaunch code constructs a new reset vector
; somewhere else and sets its
!macro NEW_RESET_VECTOR .addr {
lda #$2C
sta .addr
lda #$88
sta .addr+1
lda #$C0
sta .addr+2
lda #$6C ; JMP ($FFFC) points to 'Reenter'
sta .addr+3
lda #$FC
sta .addr+4
lda #$FF
sta .addr+5
+RESET_VECTOR .addr
}
; for 64k games on ][+ which either hang or restart
; updates reset hook to reboot on ctrl-reset
!macro LC_REBOOT {
inc $101 ; (assumes LC is switched in)
lda #$A6
sta $104
lda #$FA
sta $105 ; update reset hook to reboot
lda #1
sta $FFFD
lsr
sta $FFFC ; LC reset vector fix
}