diff options
| -rw-r--r-- | tcg/i386/tcg-target.inc.c | 35 |
1 files changed, 13 insertions, 22 deletions
diff --git a/tcg/i386/tcg-target.inc.c b/tcg/i386/tcg-target.inc.c index 01177a916d..6489b73862 100644 --- a/tcg/i386/tcg-target.inc.c +++ b/tcg/i386/tcg-target.inc.c @@ -1148,12 +1148,9 @@ static void tcg_out_ctz(TCGContext *s, int rexw, TCGReg dest, TCGReg arg1, tcg_debug_assert(arg2 == (rexw ? 64 : 32)); tcg_out_modrm(s, OPC_TZCNT + rexw, dest, arg1); } else { - /* ??? The manual says that the output is undefined when the - input is zero, but real hardware leaves it unchanged. As - noted in target-i386/translate.c, real programs depend on - this -- now we are one more of those. */ - tcg_debug_assert(dest == arg2); + tcg_debug_assert(dest != arg2); tcg_out_modrm(s, OPC_BSF + rexw, dest, arg1); + tcg_out_cmov(s, TCG_COND_EQ, rexw, dest, arg2); } } @@ -1166,26 +1163,20 @@ static void tcg_out_clz(TCGContext *s, int rexw, TCGReg dest, TCGReg arg1, tcg_debug_assert(arg2 == (rexw ? 64 : 32)); } else { tcg_debug_assert(dest != arg2); - /* LZCNT sets C if the input was zero. */ tcg_out_cmov(s, TCG_COND_LTU, rexw, dest, arg2); } } else { - TCGType type = rexw ? TCG_TYPE_I64: TCG_TYPE_I32; - TCGArg rev = rexw ? 63 : 31; + tcg_debug_assert(!const_a2); + tcg_debug_assert(dest != arg1); + tcg_debug_assert(dest != arg2); - /* Recall that the output of BSR is the index not the count. - Therefore we must adjust the result by ^ (SIZE-1). In some - cases below, we prefer an extra XOR to a JMP. */ - /* ??? See the comment in tcg_out_ctz re BSF. */ - if (const_a2) { - tcg_debug_assert(dest != arg1); - tcg_out_movi(s, type, dest, arg2 ^ rev); - } else { - tcg_debug_assert(dest == arg2); - tgen_arithi(s, ARITH_XOR + rexw, dest, rev, 0); - } + /* Recall that the output of BSR is the index not the count. */ tcg_out_modrm(s, OPC_BSR + rexw, dest, arg1); - tgen_arithi(s, ARITH_XOR + rexw, dest, rev, 0); + tgen_arithi(s, ARITH_XOR + rexw, dest, rexw ? 63 : 31, 0); + + /* Since we have destroyed the flags from BSR, we have to re-test. */ + tcg_out_cmp(s, arg1, 0, 1, rexw); + tcg_out_cmov(s, TCG_COND_EQ, rexw, dest, arg2); } } @@ -2459,7 +2450,7 @@ static const TCGTargetOpDef *tcg_target_op_def(TCGOpcode op) case INDEX_op_ctz_i64: { static const TCGTargetOpDef ctz[2] = { - { .args_ct_str = { "r", "r", "0" } }, + { .args_ct_str = { "&r", "r", "r" } }, { .args_ct_str = { "&r", "r", "rW" } }, }; return &ctz[have_bmi1]; @@ -2468,7 +2459,7 @@ static const TCGTargetOpDef *tcg_target_op_def(TCGOpcode op) case INDEX_op_clz_i64: { static const TCGTargetOpDef clz[2] = { - { .args_ct_str = { "&r", "r", "0i" } }, + { .args_ct_str = { "&r", "r", "r" } }, { .args_ct_str = { "&r", "r", "rW" } }, }; return &clz[have_lzcnt]; |