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This commit is contained in:
Dave Plummer 2024-01-29 20:22:59 -08:00
parent d266e6901c
commit 80ee84f136
1 changed files with 61 additions and 61 deletions
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122
samples/kim1/subs.asm
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@ -136,52 +136,52 @@ tempstr: .res 2
;----------------------------------------------------------------------------------- ;-----------------------------------------------------------------------------------
_GetPixelAddress: _GetPixelAddress:
lda _x1cord ; compute bit address first lda _x1cord ; compute bit address first
sta adp1 ; also transfer x1cord to adp1 sta adp1 ; also transfer x1cord to adp1
and #$07 ; + which is simply the low 3 bits of x and #$07 ; + which is simply the low 3 bits of x
sta btpt sta btpt
lda _x1cord+1 ; finish transferring x1cord to adp1 lda _x1cord+1 ; finish transferring x1cord to adp1
sta adp1+1 sta adp1+1
lsr adp1+1 ; double shift adp1 right 3 to get lsr adp1+1 ; double shift adp1 right 3 to get
ror adp1 ; int(xcord/8 ) ror adp1 ; int(xcord/8 )
lsr adp1+1 lsr adp1+1
ror adp1 ror adp1
lsr adp1+1 lsr adp1+1
ror adp1 ror adp1
sec ; and temporary storage sec ; and temporary storage
lda _y1cord lda _y1cord
sta adp2 sta adp2
sta temp sta temp
lda #0 lda #0
sbc _y1cord+1 sbc _y1cord+1
sta adp2+1 sta adp2+1
sta temp+1 sta temp+1
asl adp2 ; compute 40*(y1cord) asl adp2 ; compute 40*(y1cord)
rol adp2+1 ; 2*(y1cord) rol adp2+1 ; 2*(y1cord)
asl adp2 asl adp2
rol adp2+1 ; 4*(y1cord) rol adp2+1 ; 4*(y1cord)
lda adp2 ; add in temporary save of (y1cord) lda adp2 ; add in temporary save of (y1cord)
clc ; to make 5*(y1cord) clc ; to make 5*(y1cord)
adc temp adc temp
sta adp2 sta adp2
lda adp2+1 lda adp2+1
adc temp+1 adc temp+1
sta adp2+1 ; 5*(y1cord) sta adp2+1 ; 5*(y1cord)
asl adp2 ; 10*(1cord) asl adp2 ; 10*(1cord)
rol adp2+1 rol adp2+1
asl adp2 ; 20#(y1cord) asl adp2 ; 20#(y1cord)
rol adp2+1 rol adp2+1
asl adp2 ; 40*(y1cord) asl adp2 ; 40*(y1cord)
rol adp2+1 rol adp2+1
lda adp2 ; add in int(x1cord/8) computed earlier lda adp2 ; add in int(x1cord/8) computed earlier
clc clc
adc adp1 adc adp1
sta adp1 sta adp1
lda adp2+1 lda adp2+1
adc adp1+1 adc adp1+1
adc #>SCREEN ; add in vmorg*256 adc #>SCREEN ; add in vmorg*256
sta adp1+1 ; final result sta adp1+1 ; final result
rts ; return rts ; return
;----------------------------------------------------------------------------------- ;-----------------------------------------------------------------------------------
; Mask tables for individual pixel subroutines ; Mask tables for individual pixel subroutines
@ -190,8 +190,8 @@ _GetPixelAddress:
; MSKTB2 is a table of 0 bits corresponding to bit numbers ; MSKTB2 is a table of 0 bits corresponding to bit numbers
;----------------------------------------------------------------------------------- ;-----------------------------------------------------------------------------------
msktb1: .byte $80,$40,$20,$10,$08,$04,$02,$01 msktb1: .byte $80,$40,$20,$10,$08,$04,$02,$01
msktb2: .byte $7F,$BF,$DF,$EF,$F7,$FB,$FD,$FE msktb2: .byte $7F,$BF,$DF,$EF,$F7,$FB,$FD,$FE
_Delay: pha _Delay: pha
sta temp sta temp
@ -225,13 +225,13 @@ _Delay: pha
; Mask tables for individual pixel subroutines ; Mask tables for individual pixel subroutines
;----------------------------------------------------------------------------------- ;-----------------------------------------------------------------------------------
_SetPixel: jsr _GetPixelAddress _SetPixel: jsr _GetPixelAddress
ldy btpt ; get bit number in y ldy btpt ; get bit number in y
lda msktb1,y ; get a byte with that bit =1, others =0 lda msktb1,y ; get a byte with that bit =1, others =0
ldy #0 ldy #0
ora (adp1),y ; combine the bit with the addressed vm ora (adp1),y ; combine the bit with the addressed vm
sta (adp1),y ; byte sta (adp1),y ; byte
rts rts
;----------------------------------------------------------------------------------- ;-----------------------------------------------------------------------------------
; ClearPixel - Clears a pixel in the video memory ; ClearPixel - Clears a pixel in the video memory
@ -240,13 +240,13 @@ _SetPixel: jsr _GetPixelAddress
; y - _y1cord (16-bit) ; y - _y1cord (16-bit)
;----------------------------------------------------------------------------------- ;-----------------------------------------------------------------------------------
_ClearPixel: jsr _GetPixelAddress _ClearPixel: jsr _GetPixelAddress
ldy btpt ; get bit number in y ldy btpt ; get bit number in y
lda msktb2,y ; get a byte with that bit =0, others =1 lda msktb2,y ; get a byte with that bit =0, others =1
ldy #0 ldy #0
and (adp1),y ; remove the bit from the addressed vm and (adp1),y ; remove the bit from the addressed vm
sta (adp1),y ; byte sta (adp1),y ; byte
rts rts
;----------------------------------------------------------------------------------- ;-----------------------------------------------------------------------------------
; ClearScreen - Clears the entire video memory (and thus the screen) ; ClearScreen - Clears the entire video memory (and thus the screen)