diff options
| -rw-r--r-- | tcg/i386/tcg-target.c.inc | 49 |
1 files changed, 34 insertions, 15 deletions
diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc index a83f8aab30..29e80af78b 100644 --- a/tcg/i386/tcg-target.c.inc +++ b/tcg/i386/tcg-target.c.inc @@ -1316,23 +1316,41 @@ static void tgen_arithi(TCGContext *s, int c, int r0, c &= 7; } - /* ??? While INC is 2 bytes shorter than ADDL $1, they also induce - partial flags update stalls on Pentium4 and are not recommended - by current Intel optimization manuals. */ - if (!cf && (c == ARITH_ADD || c == ARITH_SUB) && (val == 1 || val == -1)) { - int is_inc = (c == ARITH_ADD) ^ (val < 0); - if (TCG_TARGET_REG_BITS == 64) { - /* The single-byte increment encodings are re-tasked as the - REX prefixes. Use the MODRM encoding. */ - tcg_out_modrm(s, OPC_GRP5 + rexw, - (is_inc ? EXT5_INC_Ev : EXT5_DEC_Ev), r0); - } else { - tcg_out8(s, (is_inc ? OPC_INC_r32 : OPC_DEC_r32) + r0); + switch (c) { + case ARITH_ADD: + case ARITH_SUB: + if (!cf) { + /* + * ??? While INC is 2 bytes shorter than ADDL $1, they also induce + * partial flags update stalls on Pentium4 and are not recommended + * by current Intel optimization manuals. + */ + if (val == 1 || val == -1) { + int is_inc = (c == ARITH_ADD) ^ (val < 0); + if (TCG_TARGET_REG_BITS == 64) { + /* + * The single-byte increment encodings are re-tasked + * as the REX prefixes. Use the MODRM encoding. + */ + tcg_out_modrm(s, OPC_GRP5 + rexw, + (is_inc ? EXT5_INC_Ev : EXT5_DEC_Ev), r0); + } else { + tcg_out8(s, (is_inc ? OPC_INC_r32 : OPC_DEC_r32) + r0); + } + return; + } + if (val == 128) { + /* + * Facilitate using an 8-bit immediate. Carry is inverted + * by this transformation, so do it only if cf == 0. + */ + c ^= ARITH_ADD ^ ARITH_SUB; + val = -128; + } } - return; - } + break; - if (c == ARITH_AND) { + case ARITH_AND: if (TCG_TARGET_REG_BITS == 64) { if (val == 0xffffffffu) { tcg_out_ext32u(s, r0, r0); @@ -1351,6 +1369,7 @@ static void tgen_arithi(TCGContext *s, int c, int r0, tcg_out_ext16u(s, r0, r0); return; } + break; } if (val == (int8_t)val) { |