Stacken/c64-livecoding
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make line drawing slightly faster, and make it a bit smaller

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hugova 2025-07-01 20:11:18 +02:00
parent e0314e8530
commit 3f470688a4
4 changed files with 9 additions and 15 deletions
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7
wip-hugo/routines/line/line_down.s
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@ -76,13 +76,12 @@ increment_pixel_x:
LSR byte_to_paint ; Rotates the pixel one bit to the left ON THE SCREEN.
BCC increment_pixel_x_end; We need to move to the next chunk
move_8px_left:
;; Restores byte to paint to #%10000000
ROR byte_to_paint
;; Next chunk is 8 addresses away. Look in pixel_draw for more detail.
;; -8.
;; C = 1 therefore you se 07
Add_16 btp_mem_pos, btp_mem_pos + 1, #$07, #$00, !
;; Restores byte to paint
LDA #%10000000
STA byte_to_paint
Add_16 btp_mem_pos, btp_mem_pos + 1, #$08, #$00, !
increment_pixel_x_end:
DEX
BEQ end ;We keep track on when to stop line draw with the X registry.

6
wip-hugo/routines/line/line_down_inv.s
View file

@ -61,13 +61,11 @@ increment_y_pos_end:
case_1:
Sub_16_A D, D + 1, #>V, #<V, !
increment_pixel_x:
LDA byte_to_paint
LSR byte_to_paint
BCC for_y
move_8px_left:
Add_16 btp_mem_pos, btp_mem_pos + 1, #$07, #$00, !
LDA #%10000000
STA byte_to_paint
ROR byte_to_paint
Add_16 btp_mem_pos, btp_mem_pos + 1, #$08, #$00, !
JMP for_y
case_2:
Add_16 D, D + 1, #>dx_2, #<dx_2, ! ;D = D + 2*dx

5
wip-hugo/routines/line/line_up.s
View file

@ -52,9 +52,8 @@ increment_pixel_x:
LSR byte_to_paint
BCC increment_pixel_x_end
move_8px_left:
Add_16 btp_mem_pos, btp_mem_pos + 1, #$07, #$00,!
LDA #%10000000
STA byte_to_paint
ROR byte_to_paint
Add_16 btp_mem_pos, btp_mem_pos + 1, #$08, #$00,!
increment_pixel_x_end:
DEX
;CPX X_end

6
wip-hugo/routines/line/line_up_inv.s
View file

@ -60,13 +60,11 @@ decrement_y_pos_end:
case_1:
Sub_16_A D, D + 1, #>V, #<V, !
increment_pixel_x:
LDA byte_to_paint
LSR byte_to_paint
BCC for_y
move_8px_left:
Add_16 btp_mem_pos, btp_mem_pos + 1, #$07, #$00,!
LDA #%10000000
STA byte_to_paint
ROR byte_to_paint
Add_16 btp_mem_pos, btp_mem_pos + 1, #$08, #$00,!
JMP for_y
case_2:
Add_16 D, D + 1, #>dx_2, #<dx_2, !