[Qemu-devel] [PATCH v2 06/17] target-alpha: Set fpcr_exc_status even for disabled exceptions

[Richard Henderson]

The qualifiers can suppress the raising of exceptions, but real
hardware still records that the exceptions occurred.

Reported-by: Al Viro <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>
---
 target-alpha/fpu_helper.c | 35 +++++++++++++++++++++--------------
 target-alpha/translate.c  | 28 +++++++++++++---------------
 2 files changed, 34 insertions(+), 29 deletions(-)

diff --git a/target-alpha/fpu_helper.c b/target-alpha/fpu_helper.c
index caf8317..6e84fd3 100644
--- a/target-alpha/fpu_helper.c
+++ b/target-alpha/fpu_helper.c
@@ -57,18 +57,16 @@ static uint32_t soft_to_fpcr_exc(CPUAlphaState *env)
 static void fp_exc_raise1(CPUAlphaState *env, uintptr_t retaddr,
                           uint32_t exc, uint32_t regno)
 {
-    if (exc) {
-        uint32_t hw_exc = 0;
+    uint32_t hw_exc = 0;
 
-        hw_exc |= CONVERT_BIT(exc, FPCR_INV, EXC_M_INV);
-        hw_exc |= CONVERT_BIT(exc, FPCR_DZE, EXC_M_DZE);
-        hw_exc |= CONVERT_BIT(exc, FPCR_OVF, EXC_M_FOV);
-        hw_exc |= CONVERT_BIT(exc, FPCR_UNF, EXC_M_UNF);
-        hw_exc |= CONVERT_BIT(exc, FPCR_INE, EXC_M_INE);
-        hw_exc |= CONVERT_BIT(exc, FPCR_IOV, EXC_M_IOV);
+    hw_exc |= CONVERT_BIT(exc, FPCR_INV, EXC_M_INV);
+    hw_exc |= CONVERT_BIT(exc, FPCR_DZE, EXC_M_DZE);
+    hw_exc |= CONVERT_BIT(exc, FPCR_OVF, EXC_M_FOV);
+    hw_exc |= CONVERT_BIT(exc, FPCR_UNF, EXC_M_UNF);
+    hw_exc |= CONVERT_BIT(exc, FPCR_INE, EXC_M_INE);
+    hw_exc |= CONVERT_BIT(exc, FPCR_IOV, EXC_M_IOV);
 
-        arith_excp(env, retaddr, hw_exc, 1ull << regno);
-    }
+    arith_excp(env, retaddr, hw_exc, 1ull << regno);
 }
 
 /* Raise exceptions for ieee fp insns without software completion.
@@ -76,8 +74,14 @@ static void fp_exc_raise1(CPUAlphaState *env, uintptr_t 
retaddr,
    doesn't apply.  */
 void helper_fp_exc_raise(CPUAlphaState *env, uint32_t ignore, uint32_t regno)
 {
-    uint32_t exc = env->error_code & ~ignore;
-    fp_exc_raise1(env, GETPC(), exc, regno);
+    uint32_t exc = env->error_code;
+    if (exc) {
+        env->fpcr |= exc;
+        exc &= ~ignore;
+        if (exc) {
+            fp_exc_raise1(env, GETPC(), exc, regno);
+        }
+    }
 }
 
 /* Raise exceptions for ieee fp insns with software completion.  */
@@ -86,8 +90,11 @@ void helper_fp_exc_raise_s(CPUAlphaState *env, uint32_t 
ignore, uint32_t regno)
     uint32_t exc = env->error_code & ~ignore;
     if (exc) {
         env->fpcr |= exc;
-        exc &= env->fpcr_exc_enable;
-        fp_exc_raise1(env, GETPC(), exc, regno);
+        exc &= ~ignore;
+        if (exc) {
+            exc &= env->fpcr_exc_enable;
+            fp_exc_raise1(env, GETPC(), exc, regno);
+        }
     }
 }
 
diff --git a/target-alpha/translate.c b/target-alpha/translate.c
index 25107f9..f121320 100644
--- a/target-alpha/translate.c
+++ b/target-alpha/translate.c
@@ -663,15 +663,24 @@ static TCGv gen_ieee_input(DisasContext *ctx, int reg, 
int fn11, int is_cmp)
     return val;
 }
 
-static void gen_fp_exc_raise_ignore(int rc, int fn11, int ignore)
+static void gen_fp_exc_raise(int rc, int fn11)
 {
     /* ??? We ought to be able to do something with imprecise exceptions.
        E.g. notice we're still in the trap shadow of something within the
        TB and do not generate the code to signal the exception; end the TB
        when an exception is forced to arrive, either by consumption of a
        register value or TRAPB or EXCB.  */
-    TCGv_i32 ign = tcg_const_i32(ignore);
-    TCGv_i32 reg;
+    TCGv_i32 reg, ign;
+    uint32_t ignore = 0;
+
+    if (!(fn11 & QUAL_U)) {
+        /* Note that QUAL_U == QUAL_V, so ignore either.  */
+        ignore |= FPCR_UNF | FPCR_IOV;
+    }
+    if (!(fn11 & QUAL_I)) {
+        ignore |= FPCR_INE;
+    }
+    ign = tcg_const_i32(ignore);
 
     /* ??? Pass in the regno of the destination so that the helper can
        set EXC_MASK, which contains a bitmask of destination registers
@@ -679,7 +688,6 @@ static void gen_fp_exc_raise_ignore(int rc, int fn11, int 
ignore)
        does not require this.  We do need it for a guest kernel's entArith,
        or if we were to do something clever with imprecise exceptions.  */
     reg = tcg_const_i32(rc + 32);
-
     if (fn11 & QUAL_S) {
         gen_helper_fp_exc_raise_s(cpu_env, ign, reg);
     } else {
@@ -690,11 +698,6 @@ static void gen_fp_exc_raise_ignore(int rc, int fn11, int 
ignore)
     tcg_temp_free_i32(ign);
 }
 
-static inline void gen_fp_exc_raise(int rc, int fn11)
-{
-    gen_fp_exc_raise_ignore(rc, fn11, fn11 & QUAL_I ? 0 : FPCR_INE);
-}
-
 static void gen_cvtlq(TCGv vc, TCGv vb)
 {
     TCGv tmp = tcg_temp_new();
@@ -752,7 +755,6 @@ IEEE_ARITH2(cvtts)
 static void gen_cvttq(DisasContext *ctx, int rb, int rc, int fn11)
 {
     TCGv vb, vc;
-    int ignore = 0;
 
     /* No need to set flushzero, since we have an integer output.  */
     vb = gen_ieee_input(ctx, rb, fn11, 0);
@@ -766,20 +768,16 @@ static void gen_cvttq(DisasContext *ctx, int rb, int rc, 
int fn11)
         break;
     case QUAL_V | QUAL_RM_C:
     case QUAL_S | QUAL_V | QUAL_RM_C:
-        ignore = FPCR_INE;
-        /* FALLTHRU */
     case QUAL_S | QUAL_V | QUAL_I | QUAL_RM_C:
         gen_helper_cvttq_svic(vc, cpu_env, vb);
         break;
     default:
         gen_qual_roundmode(ctx, fn11);
         gen_helper_cvttq(vc, cpu_env, vb);
-        ignore |= (fn11 & QUAL_V ? 0 : FPCR_IOV);
-        ignore |= (fn11 & QUAL_I ? 0 : FPCR_INE);
         break;
     }
 
-    gen_fp_exc_raise_ignore(rc, fn11, ignore);
+    gen_fp_exc_raise(rc, fn11);
 }
 
 static void gen_ieee_intcvt(DisasContext *ctx,
-- 
2.1.0