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encode: Make internal escape encoding more compact

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This commit is contained in:
Alexis Engelke
2021-01-07 10:03:43 +01:00
parent 3fdbd70153
commit dfb28c923d
1 changed files with 9 additions and 8 deletions
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17
encode.c
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@@ -10,9 +10,11 @@
#define UNLIKELY(x) __builtin_expect((x), 0)
enum {
// 16:17 = escape
OPC_0F = 1 << 16,
OPC_0F38 = (1 << 17) | OPC_0F,
OPC_0F3A = (1 << 18) | OPC_0F,
OPC_0F38 = 2 << 16,
OPC_0F3A = 3 << 16,
OPC_ESCAPE_MSK = 3 << 16,
OPC_66 = 1 << 19,
OPC_F2 = 1 << 20,
OPC_F3 = 1 << 21,
@@ -60,9 +62,8 @@ opc_size(uint64_t opc)
if (opc & OPC_F2) res++;
if (opc & OPC_F3) res++;
if (opc & (OPC_REX|OPC_REXW|OPC_REXR|OPC_REXX|OPC_REXB)) res++;
if (opc & OPC_0F) res++;
if ((opc & OPC_0F38) == OPC_0F38) res++;
if ((opc & OPC_0F3A) == OPC_0F3A) res++;
if (opc & OPC_ESCAPE_MSK) res++;
if ((opc & OPC_ESCAPE_MSK) == OPC_0F38 || (opc & OPC_ESCAPE_MSK) == OPC_0F3A) res++;
if ((opc & 0xc000) == 0xc000) res++;
return res;
}
@@ -87,9 +88,9 @@ enc_opc(uint8_t** restrict buf, uint64_t opc)
if (opc & OPC_REXB) rex |= 1;
*(*buf)++ = rex;
}
if (opc & OPC_0F) *(*buf)++ = 0x0F;
if ((opc & OPC_0F38) == OPC_0F38) *(*buf)++ = 0x38;
if ((opc & OPC_0F3A) == OPC_0F3A) *(*buf)++ = 0x3A;
if (opc & OPC_ESCAPE_MSK) *(*buf)++ = 0x0F;
if ((opc & OPC_ESCAPE_MSK) == OPC_0F38) *(*buf)++ = 0x38;
if ((opc & OPC_ESCAPE_MSK) == OPC_0F3A) *(*buf)++ = 0x3A;
*(*buf)++ = opc & 0xff;
if ((opc & 0xc000) == 0xc000) *(*buf)++ = (opc >> 8) & 0xff;
return 0;