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[Qemu-devel] [PULL 04/24] target-arm: Introduce DisasCompare
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PULL 04/24] target-arm: Introduce DisasCompare |
Date: |
Mon, 14 Sep 2015 14:52:51 +0100 |
From: Richard Henderson <address@hidden>
Split arm_gen_test_cc into 3 functions, so that it can be reused
for non-branch TCG comparisons.
Signed-off-by: Richard Henderson <address@hidden>
Message-id: address@hidden
Reviewed-by: Peter Maydell <address@hidden>
Signed-off-by: Peter Maydell <address@hidden>
---
target-arm/translate.c | 115 +++++++++++++++++++++++++++++--------------------
target-arm/translate.h | 9 ++++
2 files changed, 78 insertions(+), 46 deletions(-)
diff --git a/target-arm/translate.c b/target-arm/translate.c
index f1b7c16..7d2e984 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -738,81 +738,104 @@ static void gen_thumb2_parallel_addsub(int op1, int op2,
TCGv_i32 a, TCGv_i32 b)
#undef PAS_OP
/*
- * generate a conditional branch based on ARM condition code cc.
+ * Generate a conditional based on ARM condition code cc.
* This is common between ARM and Aarch64 targets.
*/
-void arm_gen_test_cc(int cc, TCGLabel *label)
+void arm_test_cc(DisasCompare *cmp, int cc)
{
- TCGv_i32 tmp;
- TCGLabel *inv;
+ TCGv_i32 value;
+ TCGCond cond;
+ bool global = true;
switch (cc) {
case 0: /* eq: Z */
- tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_ZF, 0, label);
- break;
case 1: /* ne: !Z */
- tcg_gen_brcondi_i32(TCG_COND_NE, cpu_ZF, 0, label);
+ cond = TCG_COND_EQ;
+ value = cpu_ZF;
break;
+
case 2: /* cs: C */
- tcg_gen_brcondi_i32(TCG_COND_NE, cpu_CF, 0, label);
- break;
case 3: /* cc: !C */
- tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_CF, 0, label);
+ cond = TCG_COND_NE;
+ value = cpu_CF;
break;
+
case 4: /* mi: N */
- tcg_gen_brcondi_i32(TCG_COND_LT, cpu_NF, 0, label);
- break;
case 5: /* pl: !N */
- tcg_gen_brcondi_i32(TCG_COND_GE, cpu_NF, 0, label);
+ cond = TCG_COND_LT;
+ value = cpu_NF;
break;
+
case 6: /* vs: V */
- tcg_gen_brcondi_i32(TCG_COND_LT, cpu_VF, 0, label);
- break;
case 7: /* vc: !V */
- tcg_gen_brcondi_i32(TCG_COND_GE, cpu_VF, 0, label);
+ cond = TCG_COND_LT;
+ value = cpu_VF;
break;
+
case 8: /* hi: C && !Z */
- inv = gen_new_label();
- tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_CF, 0, inv);
- tcg_gen_brcondi_i32(TCG_COND_NE, cpu_ZF, 0, label);
- gen_set_label(inv);
- break;
- case 9: /* ls: !C || Z */
- tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_CF, 0, label);
- tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_ZF, 0, label);
+ case 9: /* ls: !C || Z -> !(C && !Z) */
+ cond = TCG_COND_NE;
+ value = tcg_temp_new_i32();
+ global = false;
+ /* CF is 1 for C, so -CF is an all-bits-set mask for C;
+ ZF is non-zero for !Z; so AND the two subexpressions. */
+ tcg_gen_neg_i32(value, cpu_CF);
+ tcg_gen_and_i32(value, value, cpu_ZF);
break;
+
case 10: /* ge: N == V -> N ^ V == 0 */
- tmp = tcg_temp_new_i32();
- tcg_gen_xor_i32(tmp, cpu_VF, cpu_NF);
- tcg_gen_brcondi_i32(TCG_COND_GE, tmp, 0, label);
- tcg_temp_free_i32(tmp);
- break;
case 11: /* lt: N != V -> N ^ V != 0 */
- tmp = tcg_temp_new_i32();
- tcg_gen_xor_i32(tmp, cpu_VF, cpu_NF);
- tcg_gen_brcondi_i32(TCG_COND_LT, tmp, 0, label);
- tcg_temp_free_i32(tmp);
+ /* Since we're only interested in the sign bit, == 0 is >= 0. */
+ cond = TCG_COND_GE;
+ value = tcg_temp_new_i32();
+ global = false;
+ tcg_gen_xor_i32(value, cpu_VF, cpu_NF);
break;
+
case 12: /* gt: !Z && N == V */
- inv = gen_new_label();
- tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_ZF, 0, inv);
- tmp = tcg_temp_new_i32();
- tcg_gen_xor_i32(tmp, cpu_VF, cpu_NF);
- tcg_gen_brcondi_i32(TCG_COND_GE, tmp, 0, label);
- tcg_temp_free_i32(tmp);
- gen_set_label(inv);
- break;
case 13: /* le: Z || N != V */
- tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_ZF, 0, label);
- tmp = tcg_temp_new_i32();
- tcg_gen_xor_i32(tmp, cpu_VF, cpu_NF);
- tcg_gen_brcondi_i32(TCG_COND_LT, tmp, 0, label);
- tcg_temp_free_i32(tmp);
+ cond = TCG_COND_NE;
+ value = tcg_temp_new_i32();
+ global = false;
+ /* (N == V) is equal to the sign bit of ~(NF ^ VF). Propagate
+ * the sign bit then AND with ZF to yield the result. */
+ tcg_gen_xor_i32(value, cpu_VF, cpu_NF);
+ tcg_gen_sari_i32(value, value, 31);
+ tcg_gen_andc_i32(value, cpu_ZF, value);
break;
+
default:
fprintf(stderr, "Bad condition code 0x%x\n", cc);
abort();
}
+
+ if (cc & 1) {
+ cond = tcg_invert_cond(cond);
+ }
+
+ cmp->cond = cond;
+ cmp->value = value;
+ cmp->value_global = global;
+}
+
+void arm_free_cc(DisasCompare *cmp)
+{
+ if (!cmp->value_global) {
+ tcg_temp_free_i32(cmp->value);
+ }
+}
+
+void arm_jump_cc(DisasCompare *cmp, TCGLabel *label)
+{
+ tcg_gen_brcondi_i32(cmp->cond, cmp->value, 0, label);
+}
+
+void arm_gen_test_cc(int cc, TCGLabel *label)
+{
+ DisasCompare cmp;
+ arm_test_cc(&cmp, cc);
+ arm_jump_cc(&cmp, label);
+ arm_free_cc(&cmp);
}
static const uint8_t table_logic_cc[16] = {
diff --git a/target-arm/translate.h b/target-arm/translate.h
index a30a1db3..b8fe37a 100644
--- a/target-arm/translate.h
+++ b/target-arm/translate.h
@@ -63,6 +63,12 @@ typedef struct DisasContext {
TCGv_i64 tmp_a64[TMP_A64_MAX];
} DisasContext;
+typedef struct DisasCompare {
+ TCGCond cond;
+ TCGv_i32 value;
+ bool value_global;
+} DisasCompare;
+
/* Share the TCG temporaries common between 32 and 64 bit modes. */
extern TCGv_ptr cpu_env;
extern TCGv_i32 cpu_NF, cpu_ZF, cpu_CF, cpu_VF;
@@ -144,6 +150,9 @@ static inline void aarch64_cpu_dump_state(CPUState *cs,
FILE *f,
}
#endif
+void arm_test_cc(DisasCompare *cmp, int cc);
+void arm_free_cc(DisasCompare *cmp);
+void arm_jump_cc(DisasCompare *cmp, TCGLabel *label);
void arm_gen_test_cc(int cc, TCGLabel *label);
#endif /* TARGET_ARM_TRANSLATE_H */
--
1.9.1
- [Qemu-devel] [PULL 07/24] target-arm: Implement ccmp branchless, (continued)
- [Qemu-devel] [PULL 07/24] target-arm: Implement ccmp branchless, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 12/24] target-arm: Recognize ROR, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 06/24] target-arm: Use setcond and movcond for csel, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 15/24] i.MX: Add GPIO devices to i.MX31 SOC, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 03/24] target-arm: Share all common TCG temporaries, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 01/24] arm: xlnx-zynqmp: Fix up GIC region size, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 05/24] target-arm: Handle always condition codes within arm_test_cc, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 14/24] i.MX: Add GPIO device, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 10/24] target-arm: Recognize UXTB, UXTH, LSR, LSL, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 16/24] i.MX: Add GPIO devices to i.MX25 SOC, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 04/24] target-arm: Introduce DisasCompare,
Peter Maydell <=
- [Qemu-devel] [PULL 02/24] xlnx-zynqmp: Remove unnecessary brackets around error messages, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 18/24] target-arm: Add VTCR_EL2, Peter Maydell, 2015/09/14
- [Qemu-devel] [PULL 09/24] target-arm: Recognize SXTB, SXTH, SXTW, ASR, Peter Maydell, 2015/09/14
- Re: [Qemu-devel] [PULL 00/24] target-arm queue, Peter Maydell, 2015/09/14