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1. A fix for a bug where D gets the wrong initial value (2 bytes where flipped)

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2. Implemented line drawing for the other 3 cases
This commit is contained in:
hugova 2025-03-02 16:51:55 +01:00
parent 4f396fd740
commit 0940d9f9f9
5 changed files with 263 additions and 10 deletions
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14
wip-hugo/routines/memory/line_down.s
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@ -1,12 +1,11 @@
;;drawing line from 2 cordinates
.proc line
;;# (X_pos, Y_pos) #
;;# (X_pos, Y_pos) #
;;# * #
;;# * #
;;# * #
;;# (X_end, Y_end) #
;;
;;NOTE THAT X_pos <= X_end and line is going downwords max 45deg!
;;NOTE THAT X_pos <= X_end, Y_pos <= Y_end. Max 45deg!
;;Not values but register position in memory
X_end = $04
@ -53,10 +52,9 @@
STA >D
LDA <dy_2
STA <D
Add_16 >D, <D, #$01, #$00
Add_16 >D, <D, #$00, #$01
Sub_16 >D, <D, dx, #$00
;;We wont use dx, only 2*dx from now on
dx_2 = $0809 ;Lets reuse dx register ($08)
LDA #$00
@ -77,11 +75,9 @@ for_x:
BEQ case_2
case_1:
INC Y_pos
;; D = D - 2*dx
Sub_16 >D, <D, >dx_2, <dx_2
Sub_16 >D, <D, >dx_2, <dx_2; D = D - 2*dx
case_2:
;;D = D + 2*dy
Add_16 >D, <D, >dy_2, <dy_2
Add_16 >D, <D, >dy_2, <dy_2;D = D + 2*dy
last:
JMP for_x
end:

87
wip-hugo/routines/memory/line_down_inv.s Normal file
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@ -0,0 +1,87 @@
;;drawing line from 2 cordinates
.proc line
;;# (X_pos, Y_pos) #
;;# * #
;;# * #
;;# * #
;;# (X_end, Y_end) #
;;NOTE THAT X_pos <= X_end, Y_pos <= Y_end. Min 45deg!
;;Not values but register position in memory
X_end = $04
Y_end = $05
X_pos = $FC
Y_pos = $FB
dx_2 = $0607
dy = $08
D = $0a0b
;;Set values
LDA #$00
STA $FD ; for pixel_draw
;example values ~~~~~ SHOULD BE PRECOMPILED
LDA #$00
STA X_pos
STA Y_pos
LDA #$40
STA X_end
LDA #$a0
STA Y_end
;;~~~~~~~~~~
;;2*dx = 2*(X_end -X_pos)
LDA X_end
SEC
SBC X_pos
STA >dx_2
LDA #$00
STA <dx_2
mult_16 >dx_2, <dx_2
;;dy = (Y_end -Y_pos)
LDA Y_end
SEC
SBC Y_pos
STA dy
;;D = 2*dx - dy + 2*255. 0 <=D <= 4*255
;;Our D is bigger then wikipedia to not use negative numbers
LDA >dx_2
STA >D
LDA <dx_2
STA <D
Add_16 >D, <D, #$00, #$01
Sub_16 >D, <D, dy, #$00
;;We wont use dy, only 2*dy from now on
dy_2 = $0809 ;Lets reuse dy register ($08)
LDA #$00
STA <dy_2
mult_16 >dy_2, <dy_2
for_y:
jsr pixel_draw
;;Increment Y until Y_pos = Y_end and X_pos = X_end
INC Y_pos
LDY Y_pos
CPY Y_end
BEQ end
;;If D < %00000001 11111111 <==> >D ==0, then: case_2
LDA <D; if <D > 0 then: case_1
CMP #$00
BEQ case_2
case_1:
INC X_pos
;; D = D - 2*dx
Sub_16 >D, <D, >dy_2, <dy_2
case_2:
;;D = D + 2*dy
Add_16 >D, <D, >dx_2, <dx_2
last:
JMP for_y
end:
.endproc

85
wip-hugo/routines/memory/line_up.s Normal file
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@ -0,0 +1,85 @@
;;drawing line from 2 cordinates
.proc line
;;# * (X_end, Y_end) #
;;# #
;;# * #
;;# * #
;;# (X_pos, Y_pos) #
;;
;;NOTE THAT X_pos <= X_end, Y_pos >= Y_end. Max 45deg!
;;Not values but register position in memory
X_end = $04
Y_end = $05
X_pos = $FC
Y_pos = $FB
dy_2 = $0607
dx = $08
D = $0a0b
;;Set values
LDA #$00
STA $FD ; for pixel_draw
;example values ~~~~~ SHOULD BE PRECOMPILED
LDA #$90
STA X_pos
STA Y_pos
LDA #$aa
STA X_end
LDA #$80
STA Y_end
;;~~~~~~~~~~
;;2*dy = 2*(Y_pos-Y_end)
LDA Y_pos
SEC
SBC Y_end
STA >dy_2
LDA #$00
STA <dy_2
mult_16 >dy_2, <dy_2
;;dx = (X_end -X_pos)
LDA X_end
SEC
SBC X_pos
STA dx
;;D = 2*dy - dx + 2*255. 0 <=D <= 4*255
;;Our D is bigger then wikipedia to not use negative numbers
LDA >dy_2
STA >D
LDA <dy_2
STA <D
Add_16 >D, <D, #$00, #$01
Sub_16 >D, <D, dx, #$00
;;We wont use dx, only 2*dx from now on
dx_2 = $0809 ;Lets reuse dx register ($08)
LDA #$00
STA <dx_2
mult_16 >dx_2, <dx_2
for_x:
jsr pixel_draw
;;Increment X until X_pos = X_end and Y_pos = Y_end
INC X_pos
LDX X_pos
CPX X_end
BEQ end
;;If D < %00000001 11111111 <==> >D ==0, then: case_2
LDA <D; if <D > 0 then: case_1
CMP #$00
BEQ case_2
case_1:
DEC Y_pos
Sub_16 >D, <D, >dx_2, <dx_2; D = D -2*dx
case_2:
Add_16 >D, <D, >dy_2, <dy_2;D = D + 2*dy
last:
JMP for_x
end:
.endproc

85
wip-hugo/routines/memory/line_up_inv.s Normal file
View file

@ -0,0 +1,85 @@
;drawing line from 2 cordinates
.proc line
;;# (X_pos, Y_pos) #
;;# * #
;;# * #
;;# * #
;;# (X_end, Y_end) #
;;NOTE THAT Y_pos <= Y_end, X_pos >= X_end. Min 45deg!
;;Not values but register position in memory
X_end = $04
Y_end = $05
X_pos = $FC
Y_pos = $FB
dx_2 = $0607
dy = $08
D = $0a0b
;;Set values
LDA #$00
STA $FD ; for pixel_draw
;example values ~~~~~ SHOULD BE PRECOMPILED
LDA #$60
STA X_pos
STA Y_pos
LDA #$50
STA X_end
LDA #$90
STA Y_end
;;~~~~~~~~~~
;;2*dx = 2*(X_pos - X_end)
LDA X_pos
SEC
SBC X_end
STA >dx_2
LDA #$00
STA <dx_2
mult_16 >dx_2, <dx_2
;;dy = (Y_end -Y_pos)
LDA Y_end
SEC
SBC Y_pos
STA dy
;;D = 2*dx - dy + 2*255. 0 <=D <= 4*255
;;Our D is bigger then wikipedia to not use negative numbers
LDA >dx_2
STA >D
LDA <dx_2
STA <D
Add_16 >D, <D, #$00, #$01
Sub_16 >D, <D, dy, #$00
;;We wont use dy, only 2*dy from now on
dy_2 = $0809 ;Lets reuse dy register ($08)
LDA #$00
STA <dy_2
mult_16 >dy_2, <dy_2
for_y:
jsr pixel_draw
;;Increment Y until Y_pos = Y_end and X_pos = X_end
INC Y_pos
LDY Y_pos
CPY Y_end
BEQ end
;;If D < %00000001 11111111 <==> >D ==0, then: case_2
LDA <D; if <D > 0 then: case_1
CMP #$00
BEQ case_2
case_1:
DEC X_pos
Sub_16 >D, <D, >dy_2, <dy_2; D = D - 2*dx
case_2:
Add_16 >D, <D, >dx_2, <dx_2;D = D + 2*dy
last:
JMP for_y
end:
.endproc

2
wip-hugo/source.s
View file

@ -1,6 +1,6 @@
.include "STARTUP.s"
.include "macros/16aritmatic.s"
.include "routines/memory/line_down.s"
.include "routines/memory/line_up_inv.s"
loop_:
jmp loop_