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py/asmthumb: Provide implementations of clz/ctz for msvc. 

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George 2022-05-24 13:37:56 +10:00
parent dd35f76db3
commit aa53d2f84a
1 changed files with 19 additions and 2 deletions
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21
py/asmthumb.c
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@ -36,6 +36,23 @@
#include "py/mpstate.h"
#include "py/asmthumb.h"
#ifdef _MSC_VER
#include <intrin.h>
static uint32_t mp_clz(uint32_t x) {
unsigned long lz = 0;
return _BitScanReverse(&lz, x) ? (sizeof(x) * 8 - 1) - lz : 0;
}
static uint32_t mp_ctz(uint32_t x) {
unsigned long tz = 0;
return _BitScanForward(&tz, x) ? tz : 0;
}
#else
#define mp_clz(x) __builtin_clz(x)
#define mp_ctz(x) __builtin_ctz(x)
#endif
#define UNSIGNED_FIT5(x) ((uint32_t)(x) < 32)
#define UNSIGNED_FIT7(x) ((uint32_t)(x) < 128)
#define UNSIGNED_FIT8(x) (((x) & 0xffffff00) == 0)
@ -356,8 +373,8 @@ void asm_thumb_mov_reg_i32_optimised(asm_thumb_t *as, uint reg_dest, int i32) {
i32 = -i32;
}
uint clz = __builtin_clz(i32);
uint ctz = i32 ? __builtin_ctz(i32) : 0;
uint clz = mp_clz(i32);
uint ctz = i32 ? mp_ctz(i32) : 0;
assert(clz + ctz <= 32);
if (clz + ctz >= 24) {
asm_thumb_mov_rlo_i8(as, rlo_dest, (i32 >> ctz) & 0xff);