mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-12-26 02:00:33 +00:00
214 lines
7 KiB
C
214 lines
7 KiB
C
|
|
#include "config.h"
|
|
|
|
#include "gstgetbits.h"
|
|
|
|
/* Defined in gstgetbits_i386.s */
|
|
extern unsigned long _gst_get1bit_i386(gst_getbits_t *gb, unsigned long bits);
|
|
extern unsigned long _gst_getbits_i386(gst_getbits_t *gb, unsigned long bits);
|
|
extern unsigned long _gst_getbits_fast_i386(gst_getbits_t *gb, unsigned long bits);
|
|
extern unsigned long _gst_showbits_i386(gst_getbits_t *gb, unsigned long bits);
|
|
extern void _gst_flushbits_i386(gst_getbits_t *gb, unsigned long bits);
|
|
extern void _gst_getbits_back_i386(gst_getbits_t *gb, unsigned long bits);
|
|
|
|
/* Defined in gstgetbits_generic.c */
|
|
extern unsigned long _gst_getbits_int_cb(gst_getbits_t *gb, unsigned long bits);
|
|
extern unsigned long _gst_get1bit_int(gst_getbits_t *gb, unsigned long bits);
|
|
extern unsigned long _gst_getbits_int(gst_getbits_t *gb, unsigned long bits);
|
|
extern unsigned long _gst_getbits_fast_int(gst_getbits_t *gb, unsigned long bits);
|
|
extern unsigned long _gst_showbits_int(gst_getbits_t *gb, unsigned long bits);
|
|
extern void _gst_flushbits_int(gst_getbits_t *gb, unsigned long bits);
|
|
extern void _gst_getbits_back_int(gst_getbits_t *gb, unsigned long bits);
|
|
|
|
|
|
unsigned long gst_getbits_nBitMask[] = {
|
|
0x00000000, 0x80000000, 0xc0000000, 0xe0000000,
|
|
0xf0000000, 0xf8000000, 0xfc000000, 0xfe000000,
|
|
0xff000000, 0xff800000, 0xffc00000, 0xffe00000,
|
|
0xfff00000, 0xfff80000, 0xfffc0000, 0xfffe0000,
|
|
0xffff0000, 0xffff8000, 0xffffc000, 0xffffe000,
|
|
0xfffff000, 0xfffff800, 0xfffffc00, 0xfffffe00,
|
|
0xffffff00, 0xffffff80, 0xffffffc0, 0xffffffe0,
|
|
0xfffffff0, 0xfffffff8, 0xfffffffc, 0xfffffffe};
|
|
|
|
unsigned long _getbits_masks[] = {
|
|
0x00000000,
|
|
0x00000001, 0x00000003, 0x00000007, 0x0000000f,
|
|
0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
|
|
0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
|
|
0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
|
|
0x0001ffff, 0x0003ffff, 0x0007ffff, 0x000fffff,
|
|
0x001fffff, 0x003fffff, 0x007fffff, 0x00ffffff,
|
|
0x01ffffff, 0x03ffffff, 0x07ffffff, 0x0fffffff,
|
|
0x1fffffff, 0x3fffffff, 0x7fffffff, 0xffffffff,
|
|
};
|
|
|
|
#ifdef HAVE_LIBMMX
|
|
unsigned long _getbits_64_minus_index[] = {
|
|
64,63,62,61,60,59,58,57,56,55,54,53,52,51,50,49,48,47,46,45,44,43,42,41,
|
|
40,39,38,37,36,35,34,33,32,31,30,29,28,27,26,25,24,23,22,21,20,19,18,17,
|
|
16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1 };
|
|
|
|
/* this routine taken from Intel AppNote AP-527:
|
|
"Using MMX[tm] Instructions to Get Bits From a Data Stream"
|
|
written in C with libmmx to *closely* mimic Intel's ASM implementation
|
|
|
|
this isn't as cycle-efficient, due to the simple fact that I must call
|
|
emms() at the end. all state must be kept in *gb, not in registers */
|
|
unsigned long _gst_getbits_mmx(gst_getbits_t *gb,unsigned long bits) {
|
|
signed long remaining;
|
|
unsigned long result;
|
|
|
|
/* NOTE: this is a code-size optimization Intel seems to have missed!
|
|
according to the MMX Programmer's Reference Manual, Chapter 5,
|
|
neither movd nor movq have any effect on the flags. that means you
|
|
can put them before the sub and jl in their code, which I've done
|
|
symbolically in this C code. gcc is probably going to lose horribly,
|
|
I'll do an inline asm version later. I've a point to prove ;-) */
|
|
/* find the right shift value, put it in mm3 */
|
|
movd_m2r(_getbits_64_minus_index[bits],mm3);
|
|
/* load the current quadword into mm0 */
|
|
movq_m2r(gb->qword,mm0);
|
|
/* copy it to mm2 */
|
|
movq_r2r(mm0,mm2);
|
|
|
|
remaining = gb->bits - bits;
|
|
|
|
if (remaining <= 0) {
|
|
unsigned long dword1,dword2;
|
|
|
|
/* shift the pointer by 64 bits (8 bytes) */
|
|
gb->ptr += 8;
|
|
/* add 64 to bits remaining, to bring it positive */
|
|
remaining += 64;
|
|
|
|
/* grab the first 32 bits from the buffer and swap them around */
|
|
dword1 = swab32(*(gb->ptr-8));
|
|
/* grab the second 32 bits, swap */
|
|
dword2 = swab32(*(gb->ptr-4));
|
|
|
|
/* put second dword in mm4 */
|
|
movd_m2r(dword2,mm4);
|
|
/* shift mm2 over to make room for new bits */
|
|
psrlq_r2r(mm3,mm2);
|
|
|
|
/* put first dword in mm1 */
|
|
movd_m2r(dword1,mm1);
|
|
/* shift second dword up 32 bits */
|
|
psrlq_i2r(32,mm4);
|
|
|
|
/* put the shift counter in mm3 */
|
|
movd_m2r(remaining,mm3);
|
|
/* combine the swapped data in mm4 */
|
|
por_r2r(mm1,mm4);
|
|
|
|
/* save off the bits in mm4 to mm0 */
|
|
movq_r2r(mm4,mm0);
|
|
/* get the new low-order bits in mm4, shifted by 'mm3' */
|
|
psrlq_r2r(mm3,mm4);
|
|
|
|
/* save off new remaining bits */
|
|
gb->bits = remaining;
|
|
/* combine bits into mm2 */
|
|
por_r2r(mm2,mm4);
|
|
|
|
/* save off the result */
|
|
movd_r2m(mm2,result);
|
|
/* get rid of the bits we just read */
|
|
psllq_r2r(mm1,mm0);
|
|
|
|
/* save off mm0 */
|
|
movq_r2m(mm0,gb->qword);
|
|
|
|
/* finished with MMX */
|
|
emms();
|
|
|
|
/* we have what we came for */
|
|
return(result);
|
|
} else {
|
|
/* load the number of bits requested into mm1 */
|
|
movd_m2r(bits,mm1);
|
|
/* shift the quadword in mm2 by 'mm3' bits */
|
|
psrlq_r2r(mm3,mm2);
|
|
|
|
/* update the number of valid bits */
|
|
gb->bits = remaining;
|
|
|
|
/* save off the remaining bits */
|
|
movd_r2m(mm2,result);
|
|
/* discard those bits in mm0 */
|
|
psllq_r2r(mm1,mm0);
|
|
|
|
/* save off mm0 */
|
|
movq_r2m(mm0,gb->qword);
|
|
/* finished with MMX */
|
|
emms();
|
|
|
|
/* we have what we came for */
|
|
return(result);
|
|
}
|
|
}
|
|
#endif /* HAVE_LIBMMX */
|
|
|
|
unsigned long _gst_getbyte(gst_getbits_t *gb, unsigned long bits) {
|
|
return *gb->ptr++;
|
|
}
|
|
|
|
/* initialize the getbits structure with the proper getbits func */
|
|
void gst_getbits_init(gst_getbits_t *gb, GstGetbitsCallback callback, void *data) {
|
|
gb->ptr = NULL;
|
|
gb->bits = 0;
|
|
gb->callback = callback;
|
|
gb->data = data;
|
|
|
|
#ifdef HAVE_LIBMMX
|
|
if (1) {
|
|
gb->getbits = _gst_getbits_mmx;
|
|
// gb->backbits = _gst_getbits_back_mmx;
|
|
// gb->backbytes = _gst_getbits_byteback_mmx;
|
|
// printf("gstgetbits: using MMX optimized versions\n");
|
|
} else
|
|
#endif /* HAVE_LIBMMX */
|
|
{
|
|
if (gb->callback) {
|
|
gb->getbits = _gst_getbits_int_cb;
|
|
gb->showbits = _gst_showbits_int;
|
|
gb->flushbits = _gst_flushbits_int;
|
|
gb->backbits = _gst_getbits_back_int;
|
|
// printf("gstgetbits: using callback versions\n");
|
|
}
|
|
else {
|
|
#ifdef HAVE_CPU_I386
|
|
gb->get1bit = _gst_get1bit_i386;
|
|
gb->getbits = _gst_getbits_i386;
|
|
gb->getbits_fast = _gst_getbits_fast_i386;
|
|
gb->getbyte = _gst_getbyte;
|
|
gb->show1bit = _gst_showbits_i386;
|
|
gb->showbits = _gst_showbits_i386;
|
|
gb->flushbits = _gst_flushbits_i386;
|
|
gb->backbits = _gst_getbits_back_i386;
|
|
// printf("gstgetbits: using i386 optimized versions\n");
|
|
#else
|
|
gb->get1bit = _gst_get1bit_int;
|
|
gb->getbits = _gst_getbits_int;
|
|
gb->getbits_fast = _gst_getbits_fast_int;
|
|
gb->getbyte = _gst_getbyte;
|
|
gb->show1bit = _gst_showbits_int;
|
|
gb->showbits = _gst_showbits_int;
|
|
gb->flushbits = _gst_flushbits_int;
|
|
gb->backbits = _gst_getbits_back_int;
|
|
// printf("gstgetbits: using normal versions\n");
|
|
#endif
|
|
}
|
|
}
|
|
}
|
|
|
|
/* set up the getbits structure with a new buffer */
|
|
void gst_getbits_newbuf(gst_getbits_t *gb,unsigned char *buffer, unsigned long len) {
|
|
gb->ptr = buffer;
|
|
gb->endptr = buffer+len;
|
|
gb->bits = 0;
|
|
#ifdef HAVE_LIBMMX
|
|
// gb->qword = 0;
|
|
#endif /* HAVE_LIBMMX */
|
|
}
|