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26 * \file read_rgba_span_x86.S
27 * Optimized routines to transfer pixel data from the framebuffer to a
28 * buffer in main memory.
30 * \author Ian Romanick <idr@us.ibm.com>
33 .file "read_rgba_span_x86.S"
34 #if !defined(__DJGPP__) && !defined(__MINGW32__) /* this one cries for assyntax.h */
50 /* I implemented these as macros because the appear in quite a few places,
51 * and I've tweaked them a number of times. I got tired of changing every
52 * place they appear. :)
55 #define DO_ONE_PIXEL() \
58 bswap %eax /* ARGB -> BGRA */ ; \
59 rorl $8, %eax /* BGRA -> ABGR */ ; \
60 movl %eax, (%ecx) /* ABGR -> R, G, B, A */ ; \
63 #define DO_ONE_LAST_PIXEL() \
65 bswap %eax /* ARGB -> BGRA */ ; \
66 rorl $8, %eax /* BGRA -> ABGR */ ; \
67 movl %eax, (%ecx) /* ABGR -> R, G, B, A */ ; \
71 * MMX optimized version of the BGRA8888_REV to RGBA copy routine.
74 * This function assumes that the caller will issue the EMMS instruction
75 * at the correct places.
78 .globl _generic_read_RGBA_span_BGRA8888_REV_MMX
79 .hidden _generic_read_RGBA_span_BGRA8888_REV_MMX
80 .type _generic_read_RGBA_span_BGRA8888_REV_MMX, @function
81 _generic_read_RGBA_span_BGRA8888_REV_MMX:
90 movl 8(%esp), %ebx /* source pointer */
91 movl 16(%esp), %edx /* number of pixels to copy */
92 movl 12(%esp), %ecx /* destination pointer */
95 je .L20 /* Bail if there's nothing to do. */
108 /* Would it be faster to unroll this loop once and process 4 pixels
109 * per pass, instead of just two?
119 /* These 9 instructions do what PSHUFB (if there were such an
120 * instruction) could do in 1. :(
141 #ifdef USE_INNER_EMMS
145 /* At this point there are either 1 or 0 pixels remaining to be
146 * converted. Convert the last pixel, if needed.
157 .size _generic_read_RGBA_span_BGRA8888_REV_MMX, .-_generic_read_RGBA_span_BGRA8888_REV_MMX
161 * SSE optimized version of the BGRA8888_REV to RGBA copy routine. SSE
162 * instructions are only actually used to read data from the framebuffer.
163 * In practice, the speed-up is pretty small.
166 * Do some more testing and determine if there's any reason to have this
167 * function in addition to the MMX version.
170 * This function assumes that the caller will issue the EMMS instruction
171 * at the correct places.
174 .globl _generic_read_RGBA_span_BGRA8888_REV_SSE
175 .hidden _generic_read_RGBA_span_BGRA8888_REV_SSE
176 .type _generic_read_RGBA_span_BGRA8888_REV_SSE, @function
177 _generic_read_RGBA_span_BGRA8888_REV_SSE:
182 #ifdef USE_INNER_EMMS
188 movl 16(%esp), %ebx /* source pointer */
189 movl 24(%esp), %edx /* number of pixels to copy */
190 movl 20(%esp), %ecx /* destination pointer */
194 andl $0xfffffff0, %esp
242 /* This would be so much better if we could just move directly from
243 * an SSE register to an MMX register. Unfortunately, that
244 * functionality wasn't introduced until SSE2 with the MOVDQ2Q
286 #ifdef USE_INNER_EMMS
291 /* At this point there are either [0, 3] pixels remaining to be
326 .size _generic_read_RGBA_span_BGRA8888_REV_SSE, .-_generic_read_RGBA_span_BGRA8888_REV_SSE
330 * SSE2 optimized version of the BGRA8888_REV to RGBA copy routine.
334 .globl _generic_read_RGBA_span_BGRA8888_REV_SSE2
335 .hidden _generic_read_RGBA_span_BGRA8888_REV_SSE2
336 .type _generic_read_RGBA_span_BGRA8888_REV_SSE2, @function
337 _generic_read_RGBA_span_BGRA8888_REV_SSE2:
342 movdqa mask+16, %xmm2
344 movl 12(%esp), %ebx /* source pointer */
345 movl 20(%esp), %edx /* number of pixels to copy */
346 movl 16(%esp), %ecx /* destination pointer */
351 /* If the source pointer isn't a multiple of 16 we have to process
352 * a few pixels the "slow" way to get the address aligned for
353 * the SSE fetch intsructions.
391 /* Would it be worth having a specialized version of this loop for
392 * the case where the destination is 16-byte aligned? That version
393 * would be identical except that it could use movedqa instead of
423 /* There may be upto 3 pixels remaining to be copied. Take care
424 * of them now. We do the 2 pixel case first because the data
457 .size _generic_read_RGBA_span_BGRA8888_REV_SSE2, .-_generic_read_RGBA_span_BGRA8888_REV_SSE2
470 /* Setting SCALE_ADJUST to 5 gives a perfect match with the classic C
471 * implementation in Mesa. Setting SCALE_ADJUST to 0 is slightly faster but
472 * at a small cost to accuracy.
475 #define SCALE_ADJUST 5
476 #if SCALE_ADJUST == 5
484 .word 0x20e8 /* (0x00ff0000 / 0x000007c0) + 1 */
485 .word 0x40c5 /* (0x00ff0000 / 0x000003f0) + 1 */
486 .word 0x839d /* (0x00ff0000 / 0x000001f0) + 1 */
488 #elif SCALE_ADJUST == 0
496 .word 0x0108 /* (0x00ff0000 / 0x0000f800) + 1 */
497 .word 0x0104 /* (0x00ff0000 / 0x0000fc00) + 1 */
498 .word 0x0108 /* (0x00ff0000 / 0x0000f800) + 1 */
501 #error SCALE_ADJUST must either be 5 or 0.
505 alpha: .long 0x00000000
509 * MMX optimized version of the RGB565 to RGBA copy routine.
513 .globl _generic_read_RGBA_span_RGB565_MMX
514 .hidden _generic_read_RGBA_span_RGB565_MMX
515 .type _generic_read_RGBA_span_RGB565_MMX, @function
517 _generic_read_RGBA_span_RGB565_MMX:
519 #ifdef USE_INNER_EMMS
523 movl 4(%esp), %eax /* source pointer */
524 movl 8(%esp), %edx /* destination pointer */
525 movl 12(%esp), %ecx /* number of pixels to copy */
535 /* Fetch 4 RGB565 pixels into %mm4. Distribute the first and
536 * second pixels into the four words of %mm0 and %mm2.
542 pshufw $0x00, %mm4, %mm0
543 pshufw $0x55, %mm4, %mm2
546 /* Mask the pixels so that each word of each register contains only
547 * one color component.
554 /* Adjust the component values so that they are as small as possible,
555 * but large enough so that we can multiply them by an unsigned 16-bit
556 * number and get a value as large as 0x00ff0000.
562 psrlw $SCALE_ADJUST, %mm0
563 psrlw $SCALE_ADJUST, %mm2
566 /* Scale the input component values to be on the range
567 * [0, 0x00ff0000]. This it the real magic of the whole routine.
574 /* Always set the alpha value to 0xff.
581 /* Pack the 16-bit values to 8-bit values and store the converted
591 pshufw $0xaa, %mm4, %mm0
592 pshufw $0xff, %mm4, %mm2
599 psrlw $SCALE_ADJUST, %mm0
600 psrlw $SCALE_ADJUST, %mm2
618 /* At this point there can be at most 3 pixels left to process. If
619 * there is either 2 or 3 left, process 2.
629 pshufw $0x00, %mm4, %mm0
630 pshufw $0x55, %mm4, %mm2
637 psrlw $SCALE_ADJUST, %mm0
638 psrlw $SCALE_ADJUST, %mm2
652 /* At this point there can be at most 1 pixel left to process.
653 * Process it if needed.
662 pshufw $0x00, %mm4, %mm0
667 psrlw $SCALE_ADJUST, %mm0
678 #ifdef USE_INNER_EMMS
682 #endif /* !defined(__DJGPP__) && !defined(__MINGW32__) */