1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _VIDEO_ATAFB_UTILS_H
3#define _VIDEO_ATAFB_UTILS_H
4
5/* ================================================================= */
6/*                      Utility Assembler Functions                  */
7/* ================================================================= */
8
9/* ====================================================================== */
10
11/* Those of a delicate disposition might like to skip the next couple of
12 * pages.
13 *
14 * These functions are drop in replacements for memmove and
15 * memset(_, 0, _). However their five instances add at least a kilobyte
16 * to the object file. You have been warned.
17 *
18 * Not a great fan of assembler for the sake of it, but I think
19 * that these routines are at least 10 times faster than their C
20 * equivalents for large blits, and that's important to the lowest level of
21 * a graphics driver. Question is whether some scheme with the blitter
22 * would be faster. I suspect not for simple text system - not much
23 * asynchrony.
24 *
25 * Code is very simple, just gruesome expansion. Basic strategy is to
26 * increase data moved/cleared at each step to 16 bytes to reduce
27 * instruction per data move overhead. movem might be faster still
28 * For more than 15 bytes, we try to align the write direction on a
29 * longword boundary to get maximum speed. This is even more gruesome.
30 * Unaligned read/write used requires 68020+ - think this is a problem?
31 *
32 * Sorry!
33 */
34
35
36/* ++roman: I've optimized Robert's original versions in some minor
37 * aspects, e.g. moveq instead of movel, let gcc choose the registers,
38 * use movem in some places...
39 * For other modes than 1 plane, lots of more such assembler functions
40 * were needed (e.g. the ones using movep or expanding color values).
41 */
42
43/* ++andreas: more optimizations:
44   subl #65536,d0 replaced by clrw d0; subql #1,d0 for dbcc
45   addal is faster than addaw
46   movep is rather expensive compared to ordinary move's
47   some functions rewritten in C for clarity, no speed loss */
48
49static inline void *fb_memclear_small(void *s, size_t count)
50{
51	if (!count)
52		return 0;
53
54	asm volatile ("\n"
55		"	lsr.l	#1,%1 ; jcc 1f ; move.b %2,-(%0)\n"
56		"1:	lsr.l	#1,%1 ; jcc 1f ; move.w %2,-(%0)\n"
57		"1:	lsr.l	#1,%1 ; jcc 1f ; move.l %2,-(%0)\n"
58		"1:	lsr.l	#1,%1 ; jcc 1f ; move.l %2,-(%0) ; move.l %2,-(%0)\n"
59		"1:"
60		: "=a" (s), "=d" (count)
61		: "d" (0), "0" ((char *)s + count), "1" (count));
62	asm volatile ("\n"
63		"	subq.l  #1,%1\n"
64		"	jcs	3f\n"
65		"	move.l	%2,%%d4; move.l %2,%%d5; move.l %2,%%d6\n"
66		"2:	movem.l	%2/%%d4/%%d5/%%d6,-(%0)\n"
67		"	dbra	%1,2b\n"
68		"3:"
69		: "=a" (s), "=d" (count)
70		: "d" (0), "0" (s), "1" (count)
71		: "d4", "d5", "d6"
72		);
73
74	return 0;
75}
76
77
78static inline void *fb_memclear(void *s, size_t count)
79{
80	if (!count)
81		return 0;
82
83	if (count < 16) {
84		asm volatile ("\n"
85			"	lsr.l	#1,%1 ; jcc 1f ; clr.b (%0)+\n"
86			"1:	lsr.l	#1,%1 ; jcc 1f ; clr.w (%0)+\n"
87			"1:	lsr.l	#1,%1 ; jcc 1f ; clr.l (%0)+\n"
88			"1:	lsr.l	#1,%1 ; jcc 1f ; clr.l (%0)+ ; clr.l (%0)+\n"
89			"1:"
90			: "=a" (s), "=d" (count)
91			: "0" (s), "1" (count));
92	} else {
93		long tmp;
94		asm volatile ("\n"
95			"	move.l	%1,%2\n"
96			"	lsr.l	#1,%2 ; jcc 1f ; clr.b (%0)+ ; subq.w #1,%1\n"
97			"	lsr.l	#1,%2 ; jcs 2f\n"  /* %0 increased=>bit 2 switched*/
98			"	clr.w	(%0)+  ; subq.w  #2,%1 ; jra 2f\n"
99			"1:	lsr.l	#1,%2 ; jcc 2f\n"
100			"	clr.w	(%0)+  ; subq.w  #2,%1\n"
101			"2:	move.w	%1,%2; lsr.l #2,%1 ; jeq 6f\n"
102			"	lsr.l	#1,%1 ; jcc 3f ; clr.l (%0)+\n"
103			"3:	lsr.l	#1,%1 ; jcc 4f ; clr.l (%0)+ ; clr.l (%0)+\n"
104			"4:	subq.l	#1,%1 ; jcs 6f\n"
105			"5:	clr.l	(%0)+; clr.l (%0)+ ; clr.l (%0)+ ; clr.l (%0)+\n"
106			"	dbra	%1,5b ; clr.w %1; subq.l #1,%1; jcc 5b\n"
107			"6:	move.w	%2,%1; btst #1,%1 ; jeq 7f ; clr.w (%0)+\n"
108			"7:	btst	#0,%1 ; jeq 8f ; clr.b (%0)+\n"
109			"8:"
110			: "=a" (s), "=d" (count), "=d" (tmp)
111			: "0" (s), "1" (count));
112	}
113
114	return 0;
115}
116
117
118static inline void *fb_memset255(void *s, size_t count)
119{
120	if (!count)
121		return 0;
122
123	asm volatile ("\n"
124		"	lsr.l	#1,%1 ; jcc 1f ; move.b %2,-(%0)\n"
125		"1:	lsr.l	#1,%1 ; jcc 1f ; move.w %2,-(%0)\n"
126		"1:	lsr.l	#1,%1 ; jcc 1f ; move.l %2,-(%0)\n"
127		"1:	lsr.l	#1,%1 ; jcc 1f ; move.l %2,-(%0) ; move.l %2,-(%0)\n"
128		"1:"
129		: "=a" (s), "=d" (count)
130		: "d" (-1), "0" ((char *)s+count), "1" (count));
131	asm volatile ("\n"
132		"	subq.l	#1,%1 ; jcs 3f\n"
133		"	move.l	%2,%%d4; move.l %2,%%d5; move.l %2,%%d6\n"
134		"2:	movem.l	%2/%%d4/%%d5/%%d6,-(%0)\n"
135		"	dbra	%1,2b\n"
136		"3:"
137		: "=a" (s), "=d" (count)
138		: "d" (-1), "0" (s), "1" (count)
139		: "d4", "d5", "d6");
140
141	return 0;
142}
143
144
145static inline void *fb_memmove(void *d, const void *s, size_t count)
146{
147	if (d < s) {
148		if (count < 16) {
149			asm volatile ("\n"
150				"	lsr.l	#1,%2 ; jcc 1f ; move.b (%1)+,(%0)+\n"
151				"1:	lsr.l	#1,%2 ; jcc 1f ; move.w (%1)+,(%0)+\n"
152				"1:	lsr.l	#1,%2 ; jcc 1f ; move.l (%1)+,(%0)+\n"
153				"1:	lsr.l	#1,%2 ; jcc 1f ; move.l (%1)+,(%0)+ ; move.l (%1)+,(%0)+\n"
154				"1:"
155				: "=a" (d), "=a" (s), "=d" (count)
156				: "0" (d), "1" (s), "2" (count));
157		} else {
158			long tmp;
159			asm volatile ("\n"
160				"	move.l	%0,%3\n"
161				"	lsr.l	#1,%3 ; jcc 1f ; move.b (%1)+,(%0)+ ; subqw #1,%2\n"
162				"	lsr.l	#1,%3 ; jcs 2f\n"  /* %0 increased=>bit 2 switched*/
163				"	move.w	(%1)+,(%0)+  ; subqw  #2,%2 ; jra 2f\n"
164				"1:	lsr.l   #1,%3 ; jcc 2f\n"
165				"	move.w	(%1)+,(%0)+  ; subqw  #2,%2\n"
166				"2:	move.w	%2,%-; lsr.l #2,%2 ; jeq 6f\n"
167				"	lsr.l	#1,%2 ; jcc 3f ; move.l (%1)+,(%0)+\n"
168				"3:	lsr.l	#1,%2 ; jcc 4f ; move.l (%1)+,(%0)+ ; move.l (%1)+,(%0)+\n"
169				"4:	subq.l	#1,%2 ; jcs 6f\n"
170				"5:	move.l	(%1)+,(%0)+; move.l (%1)+,(%0)+\n"
171				"	move.l	(%1)+,(%0)+; move.l (%1)+,(%0)+\n"
172				"	dbra	%2,5b ; clr.w %2; subq.l #1,%2; jcc 5b\n"
173				"6:	move.w	%+,%2; btst #1,%2 ; jeq 7f ; move.w (%1)+,(%0)+\n"
174				"7:	btst	#0,%2 ; jeq 8f ; move.b (%1)+,(%0)+\n"
175				"8:"
176				: "=a" (d), "=a" (s), "=d" (count), "=d" (tmp)
177				: "0" (d), "1" (s), "2" (count));
178		}
179	} else {
180		if (count < 16) {
181			asm volatile ("\n"
182				"	lsr.l	#1,%2 ; jcc 1f ; move.b -(%1),-(%0)\n"
183				"1:	lsr.l	#1,%2 ; jcc 1f ; move.w -(%1),-(%0)\n"
184				"1:	lsr.l	#1,%2 ; jcc 1f ; move.l -(%1),-(%0)\n"
185				"1:	lsr.l	#1,%2 ; jcc 1f ; move.l -(%1),-(%0) ; move.l -(%1),-(%0)\n"
186				"1:"
187				: "=a" (d), "=a" (s), "=d" (count)
188				: "0" ((char *) d + count), "1" ((char *) s + count), "2" (count));
189		} else {
190			long tmp;
191
192			asm volatile ("\n"
193				"	move.l	%0,%3\n"
194				"	lsr.l	#1,%3 ; jcc 1f ; move.b -(%1),-(%0) ; subqw #1,%2\n"
195				"	lsr.l	#1,%3 ; jcs 2f\n"  /* %0 increased=>bit 2 switched*/
196				"	move.w	-(%1),-(%0) ; subqw  #2,%2 ; jra 2f\n"
197				"1:	lsr.l	#1,%3 ; jcc 2f\n"
198				"	move.w	-(%1),-(%0) ; subqw  #2,%2\n"
199				"2:	move.w	%2,%-; lsr.l #2,%2 ; jeq 6f\n"
200				"	lsr.l	#1,%2 ; jcc 3f ; move.l -(%1),-(%0)\n"
201				"3:	lsr.l	#1,%2 ; jcc 4f ; move.l -(%1),-(%0) ; move.l -(%1),-(%0)\n"
202				"4:	subq.l	#1,%2 ; jcs 6f\n"
203				"5:	move.l	-(%1),-(%0); move.l -(%1),-(%0)\n"
204				"	move.l	-(%1),-(%0); move.l -(%1),-(%0)\n"
205				"	dbra	%2,5b ; clr.w %2; subq.l #1,%2; jcc 5b\n"
206				"6:	move.w	%+,%2; btst #1,%2 ; jeq 7f ; move.w -(%1),-(%0)\n"
207				"7:	btst	#0,%2 ; jeq 8f ; move.b -(%1),-(%0)\n"
208				"8:"
209				: "=a" (d), "=a" (s), "=d" (count), "=d" (tmp)
210				: "0" ((char *) d + count), "1" ((char *) s + count), "2" (count));
211		}
212	}
213
214	return 0;
215}
216
217
218/* ++andreas: Simple and fast version of memmove, assumes size is
219   divisible by 16, suitable for moving the whole screen bitplane */
220static inline void fast_memmove(char *dst, const char *src, size_t size)
221{
222	if (!size)
223		return;
224	if (dst < src)
225		asm volatile ("\n"
226			"1:	movem.l	(%0)+,%%d0/%%d1/%%a0/%%a1\n"
227			"	movem.l	%%d0/%%d1/%%a0/%%a1,%1@\n"
228			"	addq.l	#8,%1; addq.l #8,%1\n"
229			"	dbra	%2,1b\n"
230			"	clr.w	%2; subq.l #1,%2\n"
231			"	jcc	1b"
232			: "=a" (src), "=a" (dst), "=d" (size)
233			: "0" (src), "1" (dst), "2" (size / 16 - 1)
234			: "d0", "d1", "a0", "a1", "memory");
235	else
236		asm volatile ("\n"
237			"1:	subq.l	#8,%0; subq.l #8,%0\n"
238			"	movem.l	%0@,%%d0/%%d1/%%a0/%%a1\n"
239			"	movem.l	%%d0/%%d1/%%a0/%%a1,-(%1)\n"
240			"	dbra	%2,1b\n"
241			"	clr.w	%2; subq.l #1,%2\n"
242			"	jcc 1b"
243			: "=a" (src), "=a" (dst), "=d" (size)
244			: "0" (src + size), "1" (dst + size), "2" (size / 16 - 1)
245			: "d0", "d1", "a0", "a1", "memory");
246}
247
248#ifdef BPL
249
250/*
251 * This expands a up to 8 bit color into two longs
252 * for movel operations.
253 */
254static const u32 four2long[] = {
255	0x00000000, 0x000000ff, 0x0000ff00, 0x0000ffff,
256	0x00ff0000, 0x00ff00ff, 0x00ffff00, 0x00ffffff,
257	0xff000000, 0xff0000ff, 0xff00ff00, 0xff00ffff,
258	0xffff0000, 0xffff00ff, 0xffffff00, 0xffffffff,
259};
260
261static inline void expand8_col2mask(u8 c, u32 m[])
262{
263	m[0] = four2long[c & 15];
264#if BPL > 4
265	m[1] = four2long[c >> 4];
266#endif
267}
268
269static inline void expand8_2col2mask(u8 fg, u8 bg, u32 fgm[], u32 bgm[])
270{
271	fgm[0] = four2long[fg & 15] ^ (bgm[0] = four2long[bg & 15]);
272#if BPL > 4
273	fgm[1] = four2long[fg >> 4] ^ (bgm[1] = four2long[bg >> 4]);
274#endif
275}
276
277/*
278 * set an 8bit value to a color
279 */
280static inline void fill8_col(u8 *dst, u32 m[])
281{
282	u32 tmp = m[0];
283	dst[0] = tmp;
284	dst[2] = (tmp >>= 8);
285#if BPL > 2
286	dst[4] = (tmp >>= 8);
287	dst[6] = tmp >> 8;
288#endif
289#if BPL > 4
290	tmp = m[1];
291	dst[8] = tmp;
292	dst[10] = (tmp >>= 8);
293	dst[12] = (tmp >>= 8);
294	dst[14] = tmp >> 8;
295#endif
296}
297
298/*
299 * set an 8bit value according to foreground/background color
300 */
301static inline void fill8_2col(u8 *dst, u8 fg, u8 bg, u32 mask)
302{
303	u32 fgm[2], bgm[2], tmp;
304
305	expand8_2col2mask(fg, bg, fgm, bgm);
306
307	mask |= mask << 8;
308#if BPL > 2
309	mask |= mask << 16;
310#endif
311	tmp = (mask & fgm[0]) ^ bgm[0];
312	dst[0] = tmp;
313	dst[2] = (tmp >>= 8);
314#if BPL > 2
315	dst[4] = (tmp >>= 8);
316	dst[6] = tmp >> 8;
317#endif
318#if BPL > 4
319	tmp = (mask & fgm[1]) ^ bgm[1];
320	dst[8] = tmp;
321	dst[10] = (tmp >>= 8);
322	dst[12] = (tmp >>= 8);
323	dst[14] = tmp >> 8;
324#endif
325}
326
327static const u32 two2word[] = {
328	0x00000000, 0xffff0000, 0x0000ffff, 0xffffffff
329};
330
331static inline void expand16_col2mask(u8 c, u32 m[])
332{
333	m[0] = two2word[c & 3];
334#if BPL > 2
335	m[1] = two2word[(c >> 2) & 3];
336#endif
337#if BPL > 4
338	m[2] = two2word[(c >> 4) & 3];
339	m[3] = two2word[c >> 6];
340#endif
341}
342
343static inline void expand16_2col2mask(u8 fg, u8 bg, u32 fgm[], u32 bgm[])
344{
345	bgm[0] = two2word[bg & 3];
346	fgm[0] = two2word[fg & 3] ^ bgm[0];
347#if BPL > 2
348	bgm[1] = two2word[(bg >> 2) & 3];
349	fgm[1] = two2word[(fg >> 2) & 3] ^ bgm[1];
350#endif
351#if BPL > 4
352	bgm[2] = two2word[(bg >> 4) & 3];
353	fgm[2] = two2word[(fg >> 4) & 3] ^ bgm[2];
354	bgm[3] = two2word[bg >> 6];
355	fgm[3] = two2word[fg >> 6] ^ bgm[3];
356#endif
357}
358
359static inline u32 *fill16_col(u32 *dst, int rows, u32 m[])
360{
361	while (rows) {
362		*dst++ = m[0];
363#if BPL > 2
364		*dst++ = m[1];
365#endif
366#if BPL > 4
367		*dst++ = m[2];
368		*dst++ = m[3];
369#endif
370		rows--;
371	}
372	return dst;
373}
374
375static inline void memmove32_col(void *dst, void *src, u32 mask, u32 h, u32 bytes)
376{
377	u32 *s, *d, v;
378
379        s = src;
380        d = dst;
381        do {
382                v = (*s++ & mask) | (*d  & ~mask);
383                *d++ = v;
384#if BPL > 2
385                v = (*s++ & mask) | (*d  & ~mask);
386                *d++ = v;
387#endif
388#if BPL > 4
389                v = (*s++ & mask) | (*d  & ~mask);
390                *d++ = v;
391                v = (*s++ & mask) | (*d  & ~mask);
392                *d++ = v;
393#endif
394                d = (u32 *)((u8 *)d + bytes);
395                s = (u32 *)((u8 *)s + bytes);
396        } while (--h);
397}
398
399#endif
400
401#endif /* _VIDEO_ATAFB_UTILS_H */
402