dos33fsprogs/demos/trogdor/pt3_lib_mockingboard_patch.s
2024-01-29 21:27:35 -05:00

127 lines
2.6 KiB
ArmAsm

;===================================================================
; code to patch mockingboard if not in slot#4
;===================================================================
; this is the brute force version, we have to patch 39 locations
; see further below if you want to try a smaller, more dangerous, patch
mockingboard_patch:
lda MB_ADDR_H
sta pt3_irq_smc1+2 ; 1 *
sta pt3_irq_smc2+2 ; 2 *
sta pt3_irq_smc2+5 ; 3 *
sta pt3_irq_smc3+2 ; 4 *
sta pt3_irq_smc3+5 ; 5 *
sta pt3_irq_smc4+2 ; 6 *
sta pt3_irq_smc4+5 ; 7 *
sta pt3_irq_smc5+2 ; 8 *
sta pt3_irq_smc5+5 ; 9 *
sta pt3_irq_smc6+2 ; 10 *
sta pt3_irq_smc6+5 ; 11 *
sta pt3_irq_smc7+2 ; 12 *
sta pt3_irq_smc7+5 ; 13 *
sta mock_init_smc1+2 ; 14 *
sta mock_init_smc1+5 ; 15 *
sta mock_init_smc2+2 ; 16 *
sta mock_init_smc2+5 ; 17 *
sta reset_ay_smc1+2 ; 18 *
sta reset_ay_smc2+2 ; 19 *
sta reset_ay_smc3+2 ; 20 *
sta reset_ay_smc4+2 ; 21 *
sta write_ay_smc1+2 ; 22 *
sta write_ay_smc1+5 ; 23 *
sta write_ay_smc2+2 ; 24 *
sta write_ay_smc2+5 ; 25 *
sta write_ay_smc3+2 ; 26 *
sta write_ay_smc3+5 ; 27 *
sta write_ay_smc4+2 ; 28 *
sta write_ay_smc4+5 ; 29 *
sta write_ay_smc5+2 ; 30 *
sta write_ay_smc5+5 ; 31 *
sta write_ay_smc6+2 ; 32 *
sta write_ay_smc6+5 ; 33 *
sta setup_irq_smc1+2 ; 34 *
sta setup_irq_smc2+2 ; 35 *
sta setup_irq_smc3+2 ; 36 *
sta setup_irq_smc4+2 ; 37 *
sta setup_irq_smc5+2 ; 38 *
sta setup_irq_smc6+2 ; 39 *
sta disable_irq_smc1+2 ; 40 *
sta disable_irq_smc2+2 ; 41 *
rts
.if 0
;===================================================================
; dangerous code to patch mockingboard if not in slot#4
;===================================================================
; this code patches any $C4 value to the proper slot# if not slot4
; this can be dangerous, it might over-write other important values
; that should be $C4
; safer ways to do this:
; only do this if 2 bytes after a LDA/STA/LDX/STX
; count total and if not 39 then print error message
mockingboard_patch:
; from mockingboard_init $1BBF
; to done_pt3_irq_handler $1D85
ldx MB_ADDR_H
ldy #0
lda #<mockingboard_init
sta MB_ADDR_L
lda #>mockingboard_init
sta MB_ADDR_H
mb_patch_loop:
lda (MB_ADDR_L),Y
cmp #$C4
bne mb_patch_nomatch
txa
sta (MB_ADDR_L),Y
mb_patch_nomatch:
; 16-bit increment
inc MB_ADDR_L
bne mb_patch_oflo
inc MB_ADDR_H
mb_patch_oflo:
lda MB_ADDR_H
cmp #>done_pt3_irq_handler
bne mb_patch_loop
lda MB_ADDR_L
cmp #<done_pt3_irq_handler
bne mb_patch_loop
mb_patch_done:
stx MB_ADDR_H ; restore slot for later
rts
.endif