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 
49 static 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 
78 static 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 
118 static 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 
145 static 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 */
220 static 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  */
254 static 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 
261 static 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 
269 static 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  */
280 static 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  */
301 static 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 
327 static const u32 two2word[] = {
328 	0x00000000, 0xffff0000, 0x0000ffff, 0xffffffff
329 };
330 
331 static 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 
343 static 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 
359 static 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 
375 static 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