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#470: clean up row filters, collapse into permute

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This commit is contained in:
Cameron Kaiser 2018-01-27 13:04:49 -08:00
parent 8f15c68ae7
commit d7cd088c2b
1 changed files with 31 additions and 24 deletions
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55
gfx/ycbcr/yuv_convert_ppc.cpp
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@ -15,42 +15,49 @@ namespace gfx {
// VMX version does 16 pixels at a time.
void FilterRows_VMX(uint8* ybuf, const uint8* y0_ptr, const uint8* y1_ptr,
int source_width, int source_y_fraction) {
// splat the multiplicands. AltiVec makes this unnecessarily difficult.
register vector unsigned short vector_zero = vec_splat_u16(0);
register vector unsigned char r0, c0, c1;
register vector unsigned short y0, y1, y2, y3;
uint8 *end = ybuf + source_width;
// Although you'd think using a version with vec_avg for 50% would
// be profitable to write, in practice it doesn't seem to be used
// much if at all, so this doesn't implement one.
// Splat the multiplicands. AltiVec makes this unnecessarily difficult.
unsigned short __attribute__ ((aligned(16))) syf = source_y_fraction;
unsigned short __attribute__ ((aligned(16))) syf2 = (256 - source_y_fraction);
register vector unsigned short y1_fraction = vec_lde(0, &syf);
y1_fraction = vec_splat(y1_fraction, 0);
register vector unsigned short y0_fraction = vec_lde(0, &syf2);
y0_fraction = vec_splat(y0_fraction, 0);
register vector unsigned short vector_eight = vec_splat_u16(8);
register vector unsigned short vector_zero = vec_splat_u16(0);
register vector unsigned char vector_c_zero = vec_splat_u8(0);
uint8 *end = ybuf + source_width;
// Permute vector for combining shift and pack in one operation.
// This effectively shifts each vector down by 8 bits and packs.
register vector unsigned char vector_sh8pak =
{ 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 };
// Compute a weighted average.
do {
vector unsigned char r0;
vector unsigned char c0 = vec_ld(0, y0_ptr);
vector unsigned char c1 = vec_ld(0, y1_ptr);
c0 = vec_ld(0, y0_ptr);
c1 = vec_ld(0, y1_ptr);
// another VMX annoyance: unpackh/l are SIGNED. bastard Motorola.
register vector unsigned short y0 = vec_mergeh(vector_c_zero, c0);
register vector unsigned short y1 = vec_mergeh(vector_c_zero, c1);
register vector unsigned short y2 = vec_mergel(vector_c_zero, c0);
register vector unsigned short y3 = vec_mergel(vector_c_zero, c1);
// Expand to short, since vec_mladd does not exist for char (damn).
y0 = vec_mergeh((vector unsigned char)vector_zero, c0);
y1 = vec_mergeh((vector unsigned char)vector_zero, c1);
y2 = vec_mergel((vector unsigned char)vector_zero, c0);
y3 = vec_mergel((vector unsigned char)vector_zero, c1);
// FUSED MULTIPLY ADD, BEYOTCHES! INTEL SUX!
y1 = vec_mladd(y1, y1_fraction, vector_zero);
y0 = vec_mladd(y0, y0_fraction, y1);
y0 = vec_sr(y0, vector_eight);
// FUSED MULTIPLY ADD, BEYOTCHES! INTEL SUX!
// Interleave the operations.
y1 = vec_mladd(y1, y1_fraction, vector_zero);
y3 = vec_mladd(y3, y1_fraction, vector_zero);
y0 = vec_mladd(y0, y0_fraction, y1);
y2 = vec_mladd(y2, y0_fraction, y3);
y3 = vec_mladd(y3, y1_fraction, vector_zero);
y2 = vec_mladd(y2, y0_fraction, y3);
y2 = vec_sr(y2, vector_eight);
r0 = vec_pack(y0, y2);
// Turn vec_sr on y0/y2 and a vec_pack into a single op.
r0 = vec_perm((vector unsigned char)y0, (vector unsigned char)y2, vector_sh8pak);
vec_st(r0, 0, (unsigned char *)ybuf);
ybuf += 16;