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target-mips: add unions to access DSP elements 

Instead of playing with bit shifting, add two unions (one for 32-bit
values, one for 64-bit ones) to access all the DSP elements with the
correct type.

This make the code easier to read and less error prone, and allow GCC
to vectorize the code in some cases.

Reviewed-by: Eric Johnson <ericj@mips.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Aurelien Jarno 2013-01-01 18:02:23 +01:00
parent ad153f153d
commit 652613ab5a
1 changed files with 22 additions and 0 deletions
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22
target-mips/dsp_helper.c
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@ -20,6 +20,28 @@
#include "cpu.h"
#include "helper.h"
/* As the byte ordering doesn't matter, i.e. all columns are treated
identically, these unions can be used directly. */
typedef union {
uint8_t ub[4];
int8_t sb[4];
uint16_t uh[2];
int16_t sh[2];
uint32_t uw[1];
int32_t sw[1];
} DSP32Value;
typedef union {
uint8_t ub[8];
int8_t sb[8];
uint16_t uh[4];
int16_t sh[4];
uint32_t uw[2];
int32_t sw[2];
uint64_t ul[1];
int64_t sl[1];
} DSP64Value;
/*** MIPS DSP internal functions begin ***/
#define MIPSDSP_ABS(x) (((x) >= 0) ? x : -x)
#define MIPSDSP_OVERFLOW(a, b, c, d) (!(!((a ^ b ^ -1) & (a ^ c) & d)))