diff mbox series

[2/7] target/ppc: introduce set_dfp{64,128}() helper functions

Message ID 20190924153556.27575-3-mark.cave-ayland@ilande.co.uk (mailing list archive)
State New, archived
Headers show
Series target/ppc: DFP fixes and improvements | expand

Commit Message

Mark Cave-Ayland Sept. 24, 2019, 3:35 p.m. UTC 
The existing functions (now incorrectly) assume that the MSB and LSB of DFP
numbers are stored as consecutive 64-bit words in memory. Instead of accessing
the DFP numbers directly, introduce set_dfp{64,128}() helper functions to ease
the switch to the correct representation.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 target/ppc/dfp_helper.c | 90 ++++++++++++++++++++++-------------------
 1 file changed, 48 insertions(+), 42 deletions(-)

Comments

Richard Henderson Sept. 24, 2019, 9:27 p.m. UTC | #1 
On 9/24/19 8:35 AM, Mark Cave-Ayland wrote:
> The existing functions (now incorrectly) assume that the MSB and LSB of DFP
> numbers are stored as consecutive 64-bit words in memory. Instead of accessing
> the DFP numbers directly, introduce set_dfp{64,128}() helper functions to ease
> the switch to the correct representation.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>  target/ppc/dfp_helper.c | 90 ++++++++++++++++++++++-------------------
>  1 file changed, 48 insertions(+), 42 deletions(-)
> 
> diff --git a/target/ppc/dfp_helper.c b/target/ppc/dfp_helper.c
> index 354a4aa877..cb98780d20 100644
> --- a/target/ppc/dfp_helper.c
> +++ b/target/ppc/dfp_helper.c
> @@ -47,6 +47,17 @@ static void get_dfp128(uint64_t *dst, uint64_t *dfp)
>      dst[1] = dfp[LO_IDX];
>  }
>  
> +static void set_dfp64(uint64_t *dfp, uint64_t *src)
> +{
> +    dfp[0] = src[0];
> +}
> +
> +static void set_dfp128(uint64_t *dfp, uint64_t *src)
> +{
> +    dfp[0] = src[HI_IDX];
> +    dfp[1] = src[LO_IDX];
> +}
...
>      decimal##size##FromNumber((decimal##size *)dfp.t64, &dfp.t, &dfp.context);\
>      postprocs(&dfp);                   \
>      if (size == 64) {                  \
> -        t[0] = dfp.t64[0];             \
> +        set_dfp64(t, dfp.t64);         \
>      } else if (size == 128) {          \
> -        t[0] = dfp.t64[HI_IDX];        \
> -        t[1] = dfp.t64[LO_IDX];        \
> +        set_dfp128(t, dfp.t64);        \
>      }          

This is perhaps a bit harder to see than the get case, because POSTPROCS is in
the way.

However, we can guess, because postprocs has not been passed GETPC(), that it
cannot longjmp out, and therefore not interfere with writing back of the result
to the register file.  And, as it turns out from inspection, the set of
postprocs also does not modify dfp->t64; only looks at dfp->context.status.

Therefore, as a first step we can move postprocs down, then as a second step
combine the conversion from decNumber (dfp->t) to decimal128, and then into the
register file (t).


r~
diff mbox series

Patch

diff --git a/target/ppc/dfp_helper.c b/target/ppc/dfp_helper.c
index 354a4aa877..cb98780d20 100644
--- a/target/ppc/dfp_helper.c
+++ b/target/ppc/dfp_helper.c
@@ -47,6 +47,17 @@  static void get_dfp128(uint64_t *dst, uint64_t *dfp)
     dst[1] = dfp[LO_IDX];
 }
 
+static void set_dfp64(uint64_t *dfp, uint64_t *src)
+{
+    dfp[0] = src[0];
+}
+
+static void set_dfp128(uint64_t *dfp, uint64_t *src)
+{
+    dfp[0] = src[HI_IDX];
+    dfp[1] = src[LO_IDX];
+}
+
 struct PPC_DFP {
     CPUPPCState *env;
     uint64_t t64[2], a64[2], b64[2];
@@ -413,10 +424,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, uint64_t *b)      \
     decimal##size##FromNumber((decimal##size *)dfp.t64, &dfp.t, &dfp.context); \
     postprocs(&dfp);                                                           \
     if (size == 64) {                                                          \
-        t[0] = dfp.t64[0];                                                     \
+        set_dfp64(t, dfp.t64);                                                 \
     } else if (size == 128) {                                                  \
-        t[0] = dfp.t64[HI_IDX];                                                \
-        t[1] = dfp.t64[LO_IDX];                                                \
+        set_dfp128(t, dfp.t64);                                                \
     }                                                                          \
 }
 
@@ -735,10 +745,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *b,            \
     QUA_PPs(&dfp);                                                      \
                                                                         \
     if (size == 64) {                                                   \
-        t[0] = dfp.t64[0];                                              \
+        set_dfp64(t, dfp.t64);                                          \
     } else if (size == 128) {                                           \
-        t[0] = dfp.t64[HI_IDX];                                         \
-        t[1] = dfp.t64[LO_IDX];                                         \
+        set_dfp128(t, dfp.t64);                                         \
     }                                                                   \
 }
 
@@ -759,10 +768,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a,            \
     QUA_PPs(&dfp);                                                      \
                                                                         \
     if (size == 64) {                                                   \
-        t[0] = dfp.t64[0];                                              \
+        set_dfp64(t, dfp.t64);                                          \
     } else if (size == 128) {                                           \
-        t[0] = dfp.t64[HI_IDX];                                         \
-        t[1] = dfp.t64[LO_IDX];                                         \
+        set_dfp128(t, dfp.t64);                                         \
     }                                                                   \
 }
 
@@ -843,10 +851,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a,            \
     QUA_PPs(&dfp);                                                      \
                                                                         \
     if (size == 64) {                                                   \
-        t[0] = dfp.t64[0];                                              \
+        set_dfp64(t, dfp.t64);                                          \
     } else if (size == 128) {                                           \
-        t[0] = dfp.t64[HI_IDX];                                         \
-        t[1] = dfp.t64[LO_IDX];                                         \
+        set_dfp128(t, dfp.t64);                                         \
     }                                                                   \
 }
 
@@ -867,10 +874,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *b,                   \
     postprocs(&dfp);                                                           \
                                                                                \
     if (size == 64) {                                                          \
-        t[0] = dfp.t64[0];                                                     \
+        set_dfp64(t, dfp.t64);                                                 \
     } else if (size == 128) {                                                  \
-        t[0] = dfp.t64[HI_IDX];                                                \
-        t[1] = dfp.t64[LO_IDX];                                                \
+        set_dfp128(t, dfp.t64);                                                \
     }                                                                          \
 }
 
@@ -904,7 +910,8 @@  void helper_dctdp(CPUPPCState *env, uint64_t *t, uint64_t *b)
 
     dfp_prepare_decimal64(&dfp, 0, 0, env);
     decimal32ToNumber((decimal32 *)&b_short, &dfp.t);
-    decimal64FromNumber((decimal64 *)t, &dfp.t, &dfp.context);
+    decimal64FromNumber((decimal64 *)&dfp.t64, &dfp.t, &dfp.context);
+    set_dfp64(t, dfp.t64);
     dfp_set_FPRF_from_FRT(&dfp);
 }
 
@@ -920,14 +927,14 @@  void helper_dctqpq(CPUPPCState *env, uint64_t *t, uint64_t *b)
     dfp_set_FPRF_from_FRT(&dfp);
 
     decimal128FromNumber((decimal128 *)&dfp.t64, &dfp.t, &dfp.context);
-    t[0] = dfp.t64[HI_IDX];
-    t[1] = dfp.t64[LO_IDX];
+    set_dfp128(t, dfp.t64);
 }
 
 void helper_drsp(CPUPPCState *env, uint64_t *t, uint64_t *b)
 {
     struct PPC_DFP dfp;
     uint32_t t_short = 0;
+    uint64_t t64;
     dfp_prepare_decimal64(&dfp, 0, b, env);
     decimal32FromNumber((decimal32 *)&t_short, &dfp.b, &dfp.context);
     decimal32ToNumber((decimal32 *)&t_short, &dfp.t);
@@ -937,7 +944,8 @@  void helper_drsp(CPUPPCState *env, uint64_t *t, uint64_t *b)
     dfp_check_for_UX(&dfp);
     dfp_check_for_XX(&dfp);
 
-    *t = t_short;
+    t64 = (uint64_t)t_short;
+    set_dfp64(t, &t64);
 }
 
 void helper_drdpq(CPUPPCState *env, uint64_t *t, uint64_t *b)
@@ -953,9 +961,9 @@  void helper_drdpq(CPUPPCState *env, uint64_t *t, uint64_t *b)
     dfp_check_for_UX(&dfp);
     dfp_check_for_XX(&dfp);
 
+    dfp.t64[0] = dfp.t64[1] = 0;
     decimal64FromNumber((decimal64 *)dfp.t64, &dfp.t, &dfp.context);
-    t[0] = dfp.t64[0];
-    t[1] = 0;
+    set_dfp128(t, dfp.t64);
 }
 
 #define DFP_HELPER_CFFIX(op, size)                                             \
@@ -970,10 +978,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *b)                   \
     CFFIX_PPs(&dfp);                                                           \
                                                                                \
     if (size == 64) {                                                          \
-        t[0] = dfp.t64[0];                                                     \
+        set_dfp64(t, dfp.t64);                                                 \
     } else if (size == 128) {                                                  \
-        t[0] = dfp.t64[HI_IDX];                                                \
-        t[1] = dfp.t64[LO_IDX];                                                \
+        set_dfp128(t, dfp.t64);                                                \
     }                                                                          \
 }
 
@@ -1016,7 +1023,7 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *b)                  \
         }                                                                     \
     }                                                                         \
                                                                               \
-    *t = dfp.t64[0];                                                          \
+    set_dfp64(t, dfp.t64);                                                    \
 }
 
 DFP_HELPER_CTFIX(dctfix, 64)
@@ -1078,10 +1085,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *b, uint32_t sp) \
     }                                                                     \
                                                                           \
     if (size == 64) {                                                     \
-        t[0] = dfp.t64[0];                                                \
+        set_dfp64(t, dfp.t64);                                            \
     } else if (size == 128) {                                             \
-        t[0] = dfp.t64[HI_IDX];                                           \
-        t[1] = dfp.t64[LO_IDX];                                           \
+        set_dfp128(t, dfp.t64);                                           \
     }                                                                     \
 }
 
@@ -1150,10 +1156,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *b, uint32_t s)     \
                               &dfp.context);                                 \
     dfp_set_FPRF_from_FRT(&dfp);                                             \
     if ((size) == 64) {                                                      \
-        t[0] = dfp.t64[0];                                                   \
+        set_dfp64(t, dfp.t64);                                               \
     } else if ((size) == 128) {                                              \
-        t[0] = dfp.t64[HI_IDX];                                              \
-        t[1] = dfp.t64[LO_IDX];                                              \
+        set_dfp128(t, dfp.t64);                                              \
     }                                                                        \
 }
 
@@ -1164,27 +1169,30 @@  DFP_HELPER_ENBCD(denbcdq, 128)
 void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *b)   \
 {                                                              \
     struct PPC_DFP dfp;                                        \
+    uint64_t t64;                                              \
                                                                \
     dfp_prepare_decimal##size(&dfp, 0, b, env);                \
                                                                \
     if (unlikely(decNumberIsSpecial(&dfp.b))) {                \
         if (decNumberIsInfinite(&dfp.b)) {                     \
-            *t = -1;                                           \
+            t64 = -1;                                          \
         } else if (decNumberIsSNaN(&dfp.b)) {                  \
-            *t = -3;                                           \
+            t64 = -3;                                          \
         } else if (decNumberIsQNaN(&dfp.b)) {                  \
-            *t = -2;                                           \
+            t64 = -2;                                          \
         } else {                                               \
             assert(0);                                         \
         }                                                      \
+        set_dfp64(t, &t64);                                    \
     } else {                                                   \
         if ((size) == 64) {                                    \
-            *t = dfp.b.exponent + 398;                         \
+            t64 = dfp.b.exponent + 398;                        \
         } else if ((size) == 128) {                            \
-            *t = dfp.b.exponent + 6176;                        \
+            t64 = dfp.b.exponent + 6176;                       \
         } else {                                               \
             assert(0);                                         \
         }                                                      \
+        set_dfp64(t, &t64);                                    \
     }                                                          \
 }
 
@@ -1251,10 +1259,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, uint64_t *b) \
                                   &dfp.context);                          \
     }                                                                     \
     if (size == 64) {                                                     \
-        t[0] = dfp.t64[0];                                                \
+        set_dfp64(t, dfp.t64);                                            \
     } else if (size == 128) {                                             \
-        t[0] = dfp.t64[HI_IDX];                                           \
-        t[1] = dfp.t64[LO_IDX];                                           \
+        set_dfp128(t, dfp.t64);                                           \
     }                                                                     \
 }
 
@@ -1344,10 +1351,9 @@  void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a,        \
     }                                                               \
                                                                     \
     if ((size) == 64) {                                             \
-        t[0] = dfp.t64[0];                                          \
+        set_dfp64(t, dfp.t64);                                      \
     } else {                                                        \
-        t[0] = dfp.t64[HI_IDX];                                     \
-        t[1] = dfp.t64[LO_IDX];                                     \
+        set_dfp128(t, dfp.t64);                                     \
     }                                                               \
 }