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2026-06-16 15:59:24 +00:00 · 2022-08-21 04:07:57 -05:00
parent 74dbd37f30
commit 4b9382ddbc
1392 changed files with 607600 additions and 607600 deletions
@@ -0,0 +1,182 @@
+;
+; grafix --- cgagrafa.asm
+;
+; stuff to plot points fast in 8086 assembler (BLEECH!!!)
+;
+; Written 4/87 by Scott Snyder (ssnyder@romeo.caltech.edu or @citromeo.bitnet)
+;
+; Modified 5/29/87 by sss to allow for different memory models
+;
+
+	title	cgagrafa
+
+include macros.ah
+
+sseg
+endss
+
+g_oddoff equ	02000h
+g_linsiz equ	80
+
+dseg
+
+	ex g_drawbuf,     dword
+	ex g_pixbyte,     word
+	ex g_bitpix,      word
+	ex g_colormask,   byte
+	ex g_cmask_tbl,   byte
+	ex g_hicolormask, byte
+	ex g_xor,         word
+	ex g_xcliplo,     word
+	ex g_xcliphi,     word
+	ex g_ycliplo,     word
+	ex g_ycliphi,     word
+
+endds
+
+cseg _cgagrafa
+
+; plot a point. ax = y; bl = c; cx = x;
+
+pBegin	plot
+
+	les	si, g_drawbuf		; get address of buffer
+	sar	ax, 1			; y /= 2
+	jnc	p1			; add in offset if it was odd
+	add	si, g_oddoff
+p1:	mov	dx, g_linsiz		; y * g_linsiz
+	mul	dx
+	add	si, ax			; add to offset
+	mov	ax, cx			; x to AC (ohhh... what symmetry!)
+	mov	dx, 0
+	div	g_pixbyte
+	add	si, ax			; add quotient to offset (now complete)
+	and	bl, g_colormask		; get cmask
+	mov	bl, g_cmask_tbl[bx]
+	mov	cx, g_bitpix		; only works for bitpix = 0 or 1!
+	dec	cx
+	shl	dx, cl			; dx = mask shift count
+	mov	cx, dx
+	mov	dl, g_hicolormask	; get mask
+	shr	dl, cl			; shift it
+	and	bx, dx			; bx = cmask & mask
+	mov	al, es:[si]		; get image byte
+	cmp	g_xor, 0		; xor mode?
+	jne	p2
+	not	dl			; no - (*ptr & ~mask) | (cmask & mask)
+	and	al, dl
+	or	al, bl
+	jmp	p3
+p2:	xor	al, bl			; yes - *ptr ^ (cmask & mask)
+p3:	mov	es:[si], al		; done!
+	ret
+
+pEnd	plot
+
+;
+; C interface for point plotter
+;
+; CGA_point(x, y, c)
+;
+
+pBegin	CGA_point
+	push	bp
+	mov	bp, sp
+	push	si
+	push	di
+
+	mov	ax, [bp+argbase+2]
+	mov	bx, [bp+argbase+4]
+	mov	cx, [bp+argbase]
+	call	plot
+
+	pop	di
+	pop	si
+	mov	sp, bp
+	pop	bp
+	ret
+
+pEnd	CGA_point
+
+;
+; write for pixels for circle drawing
+;
+; void CGA_write_pix(x1, y1, x2, y2, c)
+;
+
+pBegin	CGA_write_pix
+
+	push	bp
+	mov	bp, sp
+	push	si
+	push	di
+
+	mov	bx, [bp+argbase+8]	; bx = c (for plot)
+	mov	cx, [bp+argbase]	; cx = x1
+	cmp	cx, g_xcliplo		; check for clipping
+	jb	w2
+	cmp	cx, g_xcliphi
+	ja	w2
+
+	mov	ax, [bp+argbase+2]	; ax = y1
+	cmp	ax, g_ycliplo		; do clipping
+	jb	w1
+	cmp	ax, g_ycliphi
+	ja	w1
+
+	push	bx			; plot (x1, y1)
+	push	cx
+	call	plot
+	pop	cx
+	pop	bx
+
+w1:	mov	ax, [bp+argbase+6]	; ax = y2
+	cmp	ax, g_ycliplo
+	jb	w2
+	cmp	ax, g_ycliphi
+	ja	w2
+
+	push	bx			; plot (x1, y2)
+	call	plot
+	pop	bx
+
+w2:	mov	cx, [bp+argbase+4]	; cx = x2
+	cmp	cx, g_xcliplo
+	jb	w4
+	cmp	cx, g_xcliphi
+	ja	w4
+
+	mov	ax, [bp+argbase+2]	; ax = y1
+	cmp	ax, g_ycliplo		; do clipping
+	jb	w3
+	cmp	ax, g_ycliphi
+	ja	w3
+
+	push	bx			; plot (x2, y1)
+	push	cx
+	call	plot
+	pop	cx
+	pop	bx
+
+w3:	mov	ax, [bp+argbase+6]	; ax = y2
+	cmp	ax, g_ycliplo
+	jb	w4
+	cmp	ax, g_ycliphi
+	ja	w4
+
+	call	plot			; plot (x2, y2)
+
+w4:	pop	di
+	pop	si
+	mov	sp, bp
+	pop	bp
+	ret
+
+pEnd	CGA_write_pix
+
+	df_ CGA_point
+	df_ CGA_write_pix
+
+endcs	_cgagrafa
+
+end