diff mbox

[v2,9/9] target-alpha: Fix integer overflow checking insns

Message ID 1404419347-18265-10-git-send-email-rth@twiddle.net
State New
Headers show

Commit Message

Richard Henderson July 3, 2014, 8:29 p.m. UTC
We need to write the result to the destination register before
raising any exception.  Thus inline the code for each insn, and
check for any exception after we're done.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 target-alpha/helper.h     |  7 +-----
 target-alpha/int_helper.c | 59 ++--------------------------------------------
 target-alpha/translate.c  | 60 +++++++++++++++++++++++++++++++++++++++++------
 3 files changed, 56 insertions(+), 70 deletions(-)
diff mbox

Patch

diff --git a/target-alpha/helper.h b/target-alpha/helper.h
index 173db01..2cc100b 100644
--- a/target-alpha/helper.h
+++ b/target-alpha/helper.h
@@ -1,12 +1,7 @@ 
 DEF_HELPER_3(excp, noreturn, env, int, int)
 DEF_HELPER_FLAGS_1(load_pcc, TCG_CALL_NO_RWG_SE, i64, env)
 
-DEF_HELPER_FLAGS_3(addqv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(addlv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(subqv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(sublv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(mullv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(mulqv, TCG_CALL_NO_WG, i64, env, i64, i64)
+DEF_HELPER_FLAGS_3(check_overflow, TCG_CALL_NO_WG, void, env, i64, i64)
 
 DEF_HELPER_FLAGS_1(ctpop, TCG_CALL_NO_RWG_SE, i64, i64)
 DEF_HELPER_FLAGS_1(ctlz, TCG_CALL_NO_RWG_SE, i64, i64)
diff --git a/target-alpha/int_helper.c b/target-alpha/int_helper.c
index 7a205eb..8e4537f 100644
--- a/target-alpha/int_helper.c
+++ b/target-alpha/int_helper.c
@@ -249,64 +249,9 @@  uint64_t helper_unpkbw(uint64_t op1)
             | ((op1 & 0xff000000) << 24));
 }
 
-uint64_t helper_addqv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
+void helper_check_overflow(CPUAlphaState *env, uint64_t op1, uint64_t op2)
 {
-    uint64_t tmp = op1;
-    op1 += op2;
-    if (unlikely((tmp ^ op2 ^ (-1ULL)) & (tmp ^ op1) & (1ULL << 63))) {
+    if (unlikely(op1 != op2)) {
         arith_excp(env, GETPC(), EXC_M_IOV, 0);
     }
-    return op1;
-}
-
-uint64_t helper_addlv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    uint64_t tmp = op1;
-    op1 = (uint32_t)(op1 + op2);
-    if (unlikely((tmp ^ op2 ^ (-1UL)) & (tmp ^ op1) & (1UL << 31))) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return op1;
-}
-
-uint64_t helper_subqv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    uint64_t res;
-    res = op1 - op2;
-    if (unlikely((op1 ^ op2) & (res ^ op1) & (1ULL << 63))) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return res;
-}
-
-uint64_t helper_sublv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    uint32_t res;
-    res = op1 - op2;
-    if (unlikely((op1 ^ op2) & (res ^ op1) & (1UL << 31))) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return res;
-}
-
-uint64_t helper_mullv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    int64_t res = (int64_t)op1 * (int64_t)op2;
-
-    if (unlikely((int32_t)res != res)) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return (int64_t)((int32_t)res);
-}
-
-uint64_t helper_mulqv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    uint64_t tl, th;
-
-    muls64(&tl, &th, op1, op2);
-    /* If th != 0 && th != -1, then we had an overflow */
-    if (unlikely((th + 1) > 1)) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return tl;
 }
diff --git a/target-alpha/translate.c b/target-alpha/translate.c
index 183573d..6ea33f3 100644
--- a/target-alpha/translate.c
+++ b/target-alpha/translate.c
@@ -1377,7 +1377,7 @@  static ExitStatus translate_one(DisasContext *ctx, uint32_t insn)
     uint16_t fn11;
     uint8_t opc, ra, rb, rc, fpfn, fn7, lit;
     bool islit;
-    TCGv va, vb, vc, tmp;
+    TCGv va, vb, vc, tmp, tmp2;
     TCGv_i32 t32;
     ExitStatus ret;
 
@@ -1589,11 +1589,23 @@  static ExitStatus translate_one(DisasContext *ctx, uint32_t insn)
             break;
         case 0x40:
             /* ADDL/V */
-            gen_helper_addlv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tcg_gen_ext32s_i64(tmp, va);
+            tcg_gen_ext32s_i64(vc, vb);
+            tcg_gen_add_i64(tmp, tmp, vc);
+            tcg_gen_ext32s_i64(vc, tmp);
+            gen_helper_check_overflow(cpu_env, vc, tmp);
+            tcg_temp_free(tmp);
             break;
         case 0x49:
             /* SUBL/V */
-            gen_helper_sublv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tcg_gen_ext32s_i64(tmp, va);
+            tcg_gen_ext32s_i64(vc, vb);
+            tcg_gen_sub_i64(tmp, tmp, vc);
+            tcg_gen_ext32s_i64(vc, tmp);
+            gen_helper_check_overflow(cpu_env, vc, tmp);
+            tcg_temp_free(tmp);
             break;
         case 0x4D:
             /* CMPLT */
@@ -1601,11 +1613,33 @@  static ExitStatus translate_one(DisasContext *ctx, uint32_t insn)
             break;
         case 0x60:
             /* ADDQ/V */
-            gen_helper_addqv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tmp2 = tcg_temp_new();
+            tcg_gen_eqv_i64(tmp, va, vb);
+            tcg_gen_mov_i64(tmp2, va);
+            tcg_gen_add_i64(vc, va, vb);
+            tcg_gen_xor_i64(tmp2, tmp2, vc);
+            tcg_gen_and_i64(tmp, tmp, tmp2);
+            tcg_gen_shri_i64(tmp, tmp, 63);
+            tcg_gen_movi_i64(tmp2, 0);
+            gen_helper_check_overflow(cpu_env, tmp, tmp2);
+            tcg_temp_free(tmp);
+            tcg_temp_free(tmp2);
             break;
         case 0x69:
             /* SUBQ/V */
-            gen_helper_subqv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tmp2 = tcg_temp_new();
+            tcg_gen_xor_i64(tmp, va, vb);
+            tcg_gen_mov_i64(tmp2, va);
+            tcg_gen_sub_i64(vc, va, vb);
+            tcg_gen_xor_i64(tmp2, tmp2, vc);
+            tcg_gen_and_i64(tmp, tmp, tmp2);
+            tcg_gen_shri_i64(tmp, tmp, 63);
+            tcg_gen_movi_i64(tmp2, 0);
+            gen_helper_check_overflow(cpu_env, tmp, tmp2);
+            tcg_temp_free(tmp);
+            tcg_temp_free(tmp2);
             break;
         case 0x6D:
             /* CMPLE */
@@ -1900,11 +1934,23 @@  static ExitStatus translate_one(DisasContext *ctx, uint32_t insn)
             break;
         case 0x40:
             /* MULL/V */
-            gen_helper_mullv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tcg_gen_ext32s_i64(tmp, va);
+            tcg_gen_ext32s_i64(vc, vb);
+            tcg_gen_mul_i64(tmp, tmp, vc);
+            tcg_gen_ext32s_i64(vc, tmp);
+            gen_helper_check_overflow(cpu_env, vc, tmp);
+            tcg_temp_free(tmp);
             break;
         case 0x60:
             /* MULQ/V */
-            gen_helper_mulqv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tmp2 = tcg_temp_new();
+            tcg_gen_muls2_i64(vc, tmp, va, vb);
+            tcg_gen_sari_i64(tmp2, vc, 63);
+            gen_helper_check_overflow(cpu_env, tmp, tmp2);
+            tcg_temp_free(tmp);
+            tcg_temp_free(tmp2);
             break;
         default:
             goto invalid_opc;