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- affine need_to_preserve[] to get close to linux/x86_64 ABI

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- optimize NOP fillers on x86-64 (based on GNU as implementation)
This commit is contained in:
gbeauche 2004-11-01 17:12:55 +00:00
parent 382294ef55
commit b3bd00f159
1 changed files with 28 additions and 1 deletions
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29
BasiliskII/src/uae_cpu/compiler/codegen_x86.cpp
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@ -107,7 +107,12 @@ uae_u8 call_saved[]={0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0};
- Special registers (such like the stack pointer) should not be "preserved"
by pushing, even though they are "saved" across function calls
*/
uae_u8 need_to_preserve[]={1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1};
#if defined(__x86_64__)
/* callee-saved registers as defined by Linux/x86_64 ABI: rbx, rbp, rsp, r12 - r15 */
static const uae_u8 need_to_preserve[]={0,0,0,1,0,1,0,0,0,0,0,0,1,1,1,1};
#else
static const uae_u8 need_to_preserve[]={1,1,1,1,0,1,1,1};
#endif
/* Whether classes of instructions do or don't clobber the native flags */
#define CLOBBER_MOV
@ -3139,7 +3144,28 @@ static __inline__ void raw_emit_nop_filler(int nbytes)
f32_1, f32_2, f32_3, f32_4, f32_5, f32_6, f32_7, f32_8,
f32_9, f32_10, f32_11, f32_12, f32_13, f32_14, f32_15
};
static const uae_u8 prefixes[4] = { 0x66, 0x66, 0x66, 0x66 };
#if defined(__x86_64__)
/* The recommended way to pad 64bit code is to use NOPs preceded by
maximally four 0x66 prefixes. Balance the size of nops. */
if (nbytes == 0)
return;
int i;
int nnops = (nbytes + 3) / 4;
int len = nbytes / nnops;
int remains = nbytes - nnops * len;
for (i = 0; i < remains; i++) {
emit_block(prefixes, len);
raw_nop();
}
for (; i < nnops; i++) {
emit_block(prefixes, len - 1);
raw_nop();
}
#else
int nloops = nbytes / 16;
while (nloops-- > 0)
emit_block(f32_16, sizeof(f32_16));
@ -3147,6 +3173,7 @@ static __inline__ void raw_emit_nop_filler(int nbytes)
nbytes %= 16;
if (nbytes)
emit_block(f32_patt[nbytes - 1], nbytes);
#endif
}