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cc65/libsrc/tgi/tgi_bar.s

132 lines
2.9 KiB
ArmAsm

;
; Ullrich von Bassewitz, 21.06.2002
;
; void __fastcall__ tgi_bar (int x1, int y1, int x2, int y2);
; /* Draw a bar (a filled rectangle) using the current color */
.include "tgi-kernel.inc"
.importzp ptr1, ptr2, ptr3, ptr4
.import popax, popptr1
.proc _tgi_bar
sta ptr4 ; Y2
stx ptr4+1
jsr popax
sta ptr3 ; X2
stx ptr3+1
jsr popax
sta ptr2 ; Y1
stx ptr2+1
jsr popptr1 ; X1
; Make sure X1 is less than X2. Swap both if not.
lda ptr3
cmp ptr1
lda ptr3+1
sbc ptr1+1
bpl @L1
lda ptr3
ldy ptr1
sta ptr1
sty ptr3
lda ptr3+1
ldy ptr1+1
sta ptr1+1
sty ptr3+1
; Make sure Y1 is less than Y2. Swap both if not.
@L1: lda ptr4
cmp ptr2
lda ptr4+1
sbc ptr2+1
bpl @L2
lda ptr4
ldy ptr2
sta ptr2
sty ptr4
lda ptr4+1
ldy ptr2+1
sta ptr2+1
sty ptr4+1
; Check if X2 or Y2 are negative. If so, the bar is completely out of screen.
@L2: lda ptr4+1
ora ptr3+1
bmi @L9 ; Bail out
; Check if X1 is negative. If so, clip it to the left border (zero).
bit ptr1+1
bpl @L3
lda #$00
sta ptr1
sta ptr1+1
beq @L4 ; Branch always, skip following test
; Check if X1 is beyond the right border. If so, the bar is invisible.
@L3: lda ptr1
cmp _tgi_xres
lda ptr1+1
sbc _tgi_xres
bcs @L9 ; Bail out if invisible
; Check if Y1 is negative. If so, clip it to the top border (zero).
@L4: bit ptr2+1
bpl @L5
lda #$00
sta ptr2
sta ptr2+1
beq @L6 ; Branch always, skip following test
; Check if Y1 is beyond the bottom border. If so, the bar is invisible.
@L5: lda ptr2
cmp _tgi_yres
lda ptr2+1
sbc _tgi_yres
bcs @L9 ; Bail out if invisible
; Check if X2 is larger than the maximum x coord. If so, clip it.
@L6: lda ptr3
cmp _tgi_xres
lda ptr3+1
sbc _tgi_xres+1
bcc @L7
jsr _tgi_getmaxx
sta ptr3
stx ptr3+1
; Check if Y2 is larger than the maximum y coord. If so, clip it.
@L7: lda ptr4
cmp _tgi_yres
lda ptr4+1
sbc _tgi_yres+1
bcc @L8
jsr _tgi_getmaxy
sta ptr4
stx ptr4+1
; The coordinates are now valid. Call the driver.
@L8: jmp tgi_bar
; Error exit
@L9: rts
.endproc