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Use pre-multiplication in scaler to save one multiply per color component on ARM and Coldfire, at the cost of an extra add/shift in the horizontal scaler to reduce values to a workable range. SH-1 retains the same basic math, as

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the use of 16x16->32 hardware multiplication in the earlier scaler stages saves more than removing the 32x32->40 multiply to descale output.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21091 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Andrew Mahone 2009-05-26 20:00:47 +00:00
parent c4ed88f593
commit 92785b8f2f
5 changed files with 356 additions and 212 deletions
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49
apps/plugins/pictureflow/pictureflow.c
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@ -592,25 +592,12 @@ static inline PFreal fcos(int iangle)
return fsin(iangle + (IANGLE_MAX >> 2));
}
static inline uint32_t div255(uint32_t val)
static inline unsigned scale_val(unsigned val, unsigned bits)
{
return ((((val >> 8) + val) >> 8) + val) >> 8;
val = val * ((1 << bits) - 1);
return ((val >> 8) + val + 128) >> 8;
}
#define SCALE_VAL(val,out) div255((val) * (out) + 127)
#define SCALE_VAL32(val, out) \
({ \
uint32_t val__ = (val) * (out); \
val__ = ((((val__ >> 8) + val__) >> 8) + val__ + 128) >> 8; \
val__; \
})
#define SCALE_VAL8(val, out) \
({ \
unsigned val__ = (val) * (out); \
val__ = ((val__ >> 8) + val__ + 128) >> 8; \
val__; \
})
static void output_row_8_transposed(uint32_t row, void * row_in,
struct scaler_context *ctx)
{
@ -625,9 +612,9 @@ static void output_row_8_transposed(uint32_t row, void * row_in,
unsigned r, g, b;
for (; dest < end; dest += ctx->bm->height)
{
r = SCALE_VAL8(qp->red, 31);
g = SCALE_VAL8(qp->green, 63);
b = SCALE_VAL8((qp++)->blue, 31);
r = scale_val(qp->red, 5);
g = scale_val(qp->green, 6);
b = scale_val((qp++)->blue, 5);
*dest = LCD_RGBPACK_LCD(r,g,b);
}
#endif
@ -641,19 +628,15 @@ static void output_row_32_transposed(uint32_t row, void * row_in,
#ifdef USEGSLIB
uint32_t *qp = (uint32_t*)row_in;
for (; dest < end; dest += ctx->bm->height)
*dest = SC_MUL((*qp++) + ctx->round, ctx->divisor);
*dest = SC_OUT(*qp++, ctx);
#else
struct uint32_rgb *qp = (struct uint32_rgb*)row_in;
uint32_t rb_mul = SCALE_VAL32(ctx->divisor, 31),
rb_rnd = SCALE_VAL32(ctx->round, 31),
g_mul = SCALE_VAL32(ctx->divisor, 63),
g_rnd = SCALE_VAL32(ctx->round, 63);
int r, g, b;
for (; dest < end; dest += ctx->bm->height)
{
r = SC_MUL(qp->r + rb_rnd, rb_mul);
g = SC_MUL(qp->g + g_rnd, g_mul);
b = SC_MUL(qp->b + rb_rnd, rb_mul);
r = scale_val(SC_OUT(qp->r, ctx), 5);
g = scale_val(SC_OUT(qp->g, ctx), 6);
b = scale_val(SC_OUT(qp->b, ctx), 5);
qp++;
*dest = LCD_RGBPACK_LCD(r,g,b);
}
@ -670,14 +653,14 @@ static void output_row_32_transposed_fromyuv(uint32_t row, void * row_in,
for (; dest < end; dest += ctx->bm->height)
{
unsigned r, g, b, y, u, v;
y = SC_MUL(qp->b + ctx->round, ctx->divisor);
u = SC_MUL(qp->g + ctx->round, ctx->divisor);
v = SC_MUL(qp->r + ctx->round, ctx->divisor);
y = SC_OUT(qp->b, ctx);
u = SC_OUT(qp->g, ctx);
v = SC_OUT(qp->r, ctx);
qp++;
yuv_to_rgb(y, u, v, &r, &g, &b);
r = (31 * r + (r >> 3) + 127) >> 8;
g = (63 * g + (g >> 2) + 127) >> 8;
b = (31 * b + (b >> 3) + 127) >> 8;
r = scale_val(r, 5);
g = scale_val(g, 6);
b = scale_val(b, 5);
*dest = LCD_RGBPACK_LCD(r, g, b);
}
}