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Implement earlier perfromance improvments to line_up.s

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hugova 2025-03-25 19:32:51 +01:00
parent 4497026d95
commit 0df0e666ad
1 changed files with 47 additions and 16 deletions
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63
wip-hugo/routines/line/line_up.s
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@ -12,6 +12,15 @@
.proc line_up .proc line_up
.include "line.inc"; Defines memory positions, ex X_pos .include "line.inc"; Defines memory positions, ex X_pos
;LDA #$20
;STA X_pos
;STA Y_pos
;LDA #$10
;STA Y_end
;LDA #$40
;STA X_end
;;We need to clear this memory ;;We need to clear this memory
LDA #$00 LDA #$00
STA <V STA <V
@ -19,9 +28,7 @@
STA $FD ; for pixel_draw STA $FD ; for pixel_draw
;; V = 2*(dx -dy) ;; V = 2*(dx -dy)
;; where: dy = Y_pos - Y_end, dx = X_end - X_start ;; where: dy = Y_end - Y_start, dx = OO - X_start
;; This logic is comented out because line.s does it woithout any
;;extra cost. May be needed in the future so it will stay as coments!
LDA Y_pos LDA Y_pos
SEC SEC
SBC Y_end SBC Y_end
@ -32,12 +39,18 @@
SBC X_pos SBC X_pos
STA dx STA dx
SEC SEC
SBC >dy_2 SBC >V
STA >V; <V = dx - dy STA >V; <V = dx - dy
mult_16 >V, <V; V = 2*(dx -dy) mult_16 >V, <V; V = 2*(dx -dy)
;dy_2 = dy*2 ;dy_2 = dy*2
mult_16 >dy_2, <dy_2 mult_16 >dy_2, <dy_2, !
;; D = 2*dy - dx
;; In loop we have that D = D -V
;; So D needs to be at least >=V.
;; V_max = 00000001 11111111
;; For us to work with unsigned numbers we add 00000001 11111111
;; to V and the branch logic to V!
;;D = 2*dy - dx + 2*255 ;;D = 2*dy - dx + 2*255
;;Our D is bigger then wikipedia because D is unsigned. ;;Our D is bigger then wikipedia because D is unsigned.
@ -45,25 +58,43 @@
STA >D STA >D
LDA <dy_2 LDA <dy_2
STA <D STA <D
Add_16 >D, <D, #$ff, #$01 Add_16 >D, <D, #$ff, #$01, !
Sub_16 >D, <D, dx, #$00 Sub_16 >D, <D, dx, #$00
for_x:
jsr pixel_draw jsr pixel_draw
;;Increment X until X_pos = X_end and Y_pos = Y_end ;INY ; Dont want underflow
INC X_pos ;LDY #$09
;Sub_16 >btp_mem_pos, <btp_mem_pos, #$40, #$01 ;-320
LDX X_pos LDX X_pos
for_x:
LDA byte_to_paint
ORA (>btp_mem_pos), Y
STA (>btp_mem_pos), Y
increment_pixel_x:
LSR byte_to_paint
BCC increment_pixel_x_end
move_8px_left:
Add_16 >btp_mem_pos, <btp_mem_pos, #$08, #$00
LDA #%10000000
STA byte_to_paint
increment_pixel_x_end:
INX
CPX X_end CPX X_end
BEQ end BEQ end
;;If D < %00000010 00000000: case_2
;;else case 1.
Lag_16 >D, <D, #$00, #$02, case_2 Lag_16 >D, <D, #$00, #$02, case_2
case_1: case_1:
DEC Y_pos Sub_16 >D, <D, >V, <V
Sub_16 >D, <D, >V, <V; D = D - V decrement_y_pos:
JMP for_x DEY
CPY #$ff
BNE for_x
move_8px_up:
LDY #$07
Sub_16 >btp_mem_pos, <btp_mem_pos, #$40, #$01 ;-320
jmp for_x
decrement_y_pos_end:
case_2: case_2:
Add_16 >D, <D, >dy_2, <dy_2;D = D + 2*dy Add_16 >D, <D, >dy_2, <dy_2 ;D = D + 2*dy
JMP for_x JMP for_x
end: end:
RTS RTS