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target-m68k: Optimize gen_flush_flags

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Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Richard Henderson 2015-08-14 07:59:24 -07:00 committed by Laurent Vivier
parent 9d896621c1
commit 36f0399d46
1 changed files with 52 additions and 4 deletions
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56
target-m68k/translate.c
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@ -458,18 +458,66 @@ static TCGv gen_lea_indexed(CPUM68KState *env, DisasContext *s, TCGv base)
static void gen_flush_flags(DisasContext *s)
{
TCGv tmp;
TCGv t0, t1;
switch (s->cc_op) {
case CC_OP_FLAGS:
return;
case CC_OP_ADD:
tcg_gen_mov_i32(QREG_CC_C, QREG_CC_X);
tcg_gen_mov_i32(QREG_CC_Z, QREG_CC_N);
/* Compute signed overflow for addition. */
t0 = tcg_temp_new();
t1 = tcg_temp_new();
tcg_gen_sub_i32(t0, QREG_CC_N, QREG_CC_V);
tcg_gen_xor_i32(t1, QREG_CC_N, QREG_CC_V);
tcg_gen_xor_i32(QREG_CC_V, QREG_CC_V, t0);
tcg_temp_free(t0);
tcg_gen_andc_i32(QREG_CC_V, t1, QREG_CC_V);
tcg_temp_free(t1);
break;
case CC_OP_SUB:
tcg_gen_mov_i32(QREG_CC_C, QREG_CC_X);
tcg_gen_mov_i32(QREG_CC_Z, QREG_CC_N);
/* Compute signed overflow for subtraction. */
t0 = tcg_temp_new();
t1 = tcg_temp_new();
tcg_gen_add_i32(t0, QREG_CC_N, QREG_CC_V);
tcg_gen_xor_i32(t1, QREG_CC_N, QREG_CC_V);
tcg_gen_xor_i32(QREG_CC_V, QREG_CC_V, t0);
tcg_temp_free(t0);
tcg_gen_and_i32(QREG_CC_V, QREG_CC_V, t1);
tcg_temp_free(t1);
break;
case CC_OP_CMP:
tcg_gen_setcond_i32(TCG_COND_LTU, QREG_CC_C, QREG_CC_N, QREG_CC_V);
tcg_gen_sub_i32(QREG_CC_Z, QREG_CC_N, QREG_CC_V);
/* Compute signed overflow for subtraction. */
t0 = tcg_temp_new();
tcg_gen_xor_i32(t0, QREG_CC_Z, QREG_CC_N);
tcg_gen_xor_i32(QREG_CC_V, QREG_CC_V, QREG_CC_N);
tcg_gen_and_i32(QREG_CC_V, QREG_CC_V, t0);
tcg_temp_free(t0);
tcg_gen_mov_i32(QREG_CC_N, QREG_CC_Z);
break;
case CC_OP_LOGIC:
tcg_gen_mov_i32(QREG_CC_Z, QREG_CC_N);
tcg_gen_movi_i32(QREG_CC_C, 0);
tcg_gen_movi_i32(QREG_CC_V, 0);
break;
case CC_OP_DYNAMIC:
gen_helper_flush_flags(cpu_env, QREG_CC_OP);
break;
default:
tmp = tcg_const_i32(s->cc_op);
gen_helper_flush_flags(cpu_env, tmp);
tcg_temp_free(tmp);
t0 = tcg_const_i32(s->cc_op);
gen_helper_flush_flags(cpu_env, t0);
tcg_temp_free(t0);
break;
}