diff mbox

[V4,12/14] target-ppc: VSX Stage 4: Add Scalar SP Fused Multiply-Adds

Message ID 1386258303-2684-13-git-send-email-tommusta@gmail.com
State New
Headers show

Commit Message

Tom Musta Dec. 5, 2013, 3:45 p.m. UTC 
This patch adds the Single Precision VSX Scalar Fused Multiply-Add
instructions: xsmaddasp, xsmaddmsp, xssubasp, xssubmsp, xsnmaddasp,
xsnmaddmsp, xsnmsubasp, xsnmsubmsp.

The existing VSX_MADD() macro is modified to support rounding of the
intermediate double precision result to single precision.

V2: Re-implemented per feedback from Richard Henderson.  In order to
avoid double rounding and incorrect results, the operands must be
converted to true single precision values and use the single precision
fused multiply/add routine.

V3: Re-implemented per feedback from Richard Henderson (I did not
fully understand his comment when I implemented V2).

V4: Changed to use helper_frsp (inadvertently re-injected when I used an
earlier patch).  Thanks to Richard Henderson for catching this.

Signed-off-by: Tom Musta <tommusta@gmail.com>
---
 target-ppc/fpu_helper.c |   82 ++++++++++++++++++++++++++++++----------------
 target-ppc/helper.h     |    8 ++++
 target-ppc/translate.c  |   16 +++++++++
 3 files changed, 77 insertions(+), 29 deletions(-)

Comments

Richard Henderson Dec. 5, 2013, 9:15 p.m. UTC | #1 
On 12/06/2013 04:45 AM, Tom Musta wrote:
> This patch adds the Single Precision VSX Scalar Fused Multiply-Add
> instructions: xsmaddasp, xsmaddmsp, xssubasp, xssubmsp, xsnmaddasp,
> xsnmaddmsp, xsnmsubasp, xsnmsubmsp.
> 
> The existing VSX_MADD() macro is modified to support rounding of the
> intermediate double precision result to single precision.
> 
> V2: Re-implemented per feedback from Richard Henderson.  In order to
> avoid double rounding and incorrect results, the operands must be
> converted to true single precision values and use the single precision
> fused multiply/add routine.
> 
> V3: Re-implemented per feedback from Richard Henderson (I did not
> fully understand his comment when I implemented V2).
> 
> V4: Changed to use helper_frsp (inadvertently re-injected when I used an
> earlier patch).  Thanks to Richard Henderson for catching this.
> 
> Signed-off-by: Tom Musta <tommusta@gmail.com>
> ---
>  target-ppc/fpu_helper.c |   82 ++++++++++++++++++++++++++++++----------------
>  target-ppc/helper.h     |    8 ++++
>  target-ppc/translate.c  |   16 +++++++++
>  3 files changed, 77 insertions(+), 29 deletions(-)

Reviewed-by: Richard Henderson <rth@twiddle.net>


r~
diff mbox

Patch

diff --git a/target-ppc/fpu_helper.c b/target-ppc/fpu_helper.c
index 8825db2..7926c71 100644
--- a/target-ppc/fpu_helper.c
+++ b/target-ppc/fpu_helper.c
@@ -2192,7 +2192,7 @@  VSX_TSQRT(xvtsqrtsp, 4, float32, f32, -126, 23)
  *   afrm  - A form (1=A, 0=M)
  *   sfprf - set FPRF
  */
-#define VSX_MADD(op, nels, tp, fld, maddflgs, afrm, sfprf)                    \
+#define VSX_MADD(op, nels, tp, fld, maddflgs, afrm, sfprf, r2sp)              \
 void helper_##op(CPUPPCState *env, uint32_t opcode)                           \
 {                                                                             \
     ppc_vsr_t xt_in, xa, xb, xt_out;                                          \
@@ -2218,8 +2218,18 @@  void helper_##op(CPUPPCState *env, uint32_t opcode)                           \
     for (i = 0; i < nels; i++) {                                              \
         float_status tstat = env->fp_status;                                  \
         set_float_exception_flags(0, &tstat);                                 \
-        xt_out.fld[i] = tp##_muladd(xa.fld[i], b->fld[i], c->fld[i],          \
-                                     maddflgs, &tstat);                       \
+        if (r2sp && (tstat.float_rounding_mode == float_round_nearest_even)) {\
+            /* Avoid double rounding errors by rounding the intermediate */   \
+            /* result to odd.                                            */   \
+            set_float_rounding_mode(float_round_to_zero, &tstat);             \
+            xt_out.fld[i] = tp##_muladd(xa.fld[i], b->fld[i], c->fld[i],      \
+                                       maddflgs, &tstat);                     \
+            xt_out.fld[i] |= (get_float_exception_flags(&tstat) &             \
+                              float_flag_inexact) != 0;                       \
+        } else {                                                              \
+            xt_out.fld[i] = tp##_muladd(xa.fld[i], b->fld[i], c->fld[i],      \
+                                        maddflgs, &tstat);                    \
+        }                                                                     \
         env->fp_status.float_exception_flags |= tstat.float_exception_flags;  \
                                                                               \
         if (unlikely(tstat.float_exception_flags & float_flag_invalid)) {     \
@@ -2242,6 +2252,11 @@  void helper_##op(CPUPPCState *env, uint32_t opcode)                           \
                 fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, sfprf);     \
             }                                                                 \
         }                                                                     \
+                                                                              \
+        if (r2sp) {                                                           \
+            xt_out.fld[i] = helper_frsp(env, xt_out.fld[i]);                  \
+        }                                                                     \
+                                                                              \
         if (sfprf) {                                                          \
             helper_compute_fprf(env, xt_out.fld[i], sfprf);                   \
         }                                                                     \
@@ -2255,32 +2270,41 @@  void helper_##op(CPUPPCState *env, uint32_t opcode)                           \
 #define NMADD_FLGS float_muladd_negate_result
 #define NMSUB_FLGS (float_muladd_negate_c | float_muladd_negate_result)
 
-VSX_MADD(xsmaddadp, 1, float64, f64, MADD_FLGS, 1, 1)
-VSX_MADD(xsmaddmdp, 1, float64, f64, MADD_FLGS, 0, 1)
-VSX_MADD(xsmsubadp, 1, float64, f64, MSUB_FLGS, 1, 1)
-VSX_MADD(xsmsubmdp, 1, float64, f64, MSUB_FLGS, 0, 1)
-VSX_MADD(xsnmaddadp, 1, float64, f64, NMADD_FLGS, 1, 1)
-VSX_MADD(xsnmaddmdp, 1, float64, f64, NMADD_FLGS, 0, 1)
-VSX_MADD(xsnmsubadp, 1, float64, f64, NMSUB_FLGS, 1, 1)
-VSX_MADD(xsnmsubmdp, 1, float64, f64, NMSUB_FLGS, 0, 1)
-
-VSX_MADD(xvmaddadp, 2, float64, f64, MADD_FLGS, 1, 0)
-VSX_MADD(xvmaddmdp, 2, float64, f64, MADD_FLGS, 0, 0)
-VSX_MADD(xvmsubadp, 2, float64, f64, MSUB_FLGS, 1, 0)
-VSX_MADD(xvmsubmdp, 2, float64, f64, MSUB_FLGS, 0, 0)
-VSX_MADD(xvnmaddadp, 2, float64, f64, NMADD_FLGS, 1, 0)
-VSX_MADD(xvnmaddmdp, 2, float64, f64, NMADD_FLGS, 0, 0)
-VSX_MADD(xvnmsubadp, 2, float64, f64, NMSUB_FLGS, 1, 0)
-VSX_MADD(xvnmsubmdp, 2, float64, f64, NMSUB_FLGS, 0, 0)
-
-VSX_MADD(xvmaddasp, 4, float32, f32, MADD_FLGS, 1, 0)
-VSX_MADD(xvmaddmsp, 4, float32, f32, MADD_FLGS, 0, 0)
-VSX_MADD(xvmsubasp, 4, float32, f32, MSUB_FLGS, 1, 0)
-VSX_MADD(xvmsubmsp, 4, float32, f32, MSUB_FLGS, 0, 0)
-VSX_MADD(xvnmaddasp, 4, float32, f32, NMADD_FLGS, 1, 0)
-VSX_MADD(xvnmaddmsp, 4, float32, f32, NMADD_FLGS, 0, 0)
-VSX_MADD(xvnmsubasp, 4, float32, f32, NMSUB_FLGS, 1, 0)
-VSX_MADD(xvnmsubmsp, 4, float32, f32, NMSUB_FLGS, 0, 0)
+VSX_MADD(xsmaddadp, 1, float64, f64, MADD_FLGS, 1, 1, 0)
+VSX_MADD(xsmaddmdp, 1, float64, f64, MADD_FLGS, 0, 1, 0)
+VSX_MADD(xsmsubadp, 1, float64, f64, MSUB_FLGS, 1, 1, 0)
+VSX_MADD(xsmsubmdp, 1, float64, f64, MSUB_FLGS, 0, 1, 0)
+VSX_MADD(xsnmaddadp, 1, float64, f64, NMADD_FLGS, 1, 1, 0)
+VSX_MADD(xsnmaddmdp, 1, float64, f64, NMADD_FLGS, 0, 1, 0)
+VSX_MADD(xsnmsubadp, 1, float64, f64, NMSUB_FLGS, 1, 1, 0)
+VSX_MADD(xsnmsubmdp, 1, float64, f64, NMSUB_FLGS, 0, 1, 0)
+
+VSX_MADD(xsmaddasp, 1, float64, f64, MADD_FLGS, 1, 1, 1)
+VSX_MADD(xsmaddmsp, 1, float64, f64, MADD_FLGS, 0, 1, 1)
+VSX_MADD(xsmsubasp, 1, float64, f64, MSUB_FLGS, 1, 1, 1)
+VSX_MADD(xsmsubmsp, 1, float64, f64, MSUB_FLGS, 0, 1, 1)
+VSX_MADD(xsnmaddasp, 1, float64, f64, NMADD_FLGS, 1, 1, 1)
+VSX_MADD(xsnmaddmsp, 1, float64, f64, NMADD_FLGS, 0, 1, 1)
+VSX_MADD(xsnmsubasp, 1, float64, f64, NMSUB_FLGS, 1, 1, 1)
+VSX_MADD(xsnmsubmsp, 1, float64, f64, NMSUB_FLGS, 0, 1, 1)
+
+VSX_MADD(xvmaddadp, 2, float64, f64, MADD_FLGS, 1, 0, 0)
+VSX_MADD(xvmaddmdp, 2, float64, f64, MADD_FLGS, 0, 0, 0)
+VSX_MADD(xvmsubadp, 2, float64, f64, MSUB_FLGS, 1, 0, 0)
+VSX_MADD(xvmsubmdp, 2, float64, f64, MSUB_FLGS, 0, 0, 0)
+VSX_MADD(xvnmaddadp, 2, float64, f64, NMADD_FLGS, 1, 0, 0)
+VSX_MADD(xvnmaddmdp, 2, float64, f64, NMADD_FLGS, 0, 0, 0)
+VSX_MADD(xvnmsubadp, 2, float64, f64, NMSUB_FLGS, 1, 0, 0)
+VSX_MADD(xvnmsubmdp, 2, float64, f64, NMSUB_FLGS, 0, 0, 0)
+
+VSX_MADD(xvmaddasp, 4, float32, f32, MADD_FLGS, 1, 0, 0)
+VSX_MADD(xvmaddmsp, 4, float32, f32, MADD_FLGS, 0, 0, 0)
+VSX_MADD(xvmsubasp, 4, float32, f32, MSUB_FLGS, 1, 0, 0)
+VSX_MADD(xvmsubmsp, 4, float32, f32, MSUB_FLGS, 0, 0, 0)
+VSX_MADD(xvnmaddasp, 4, float32, f32, NMADD_FLGS, 1, 0, 0)
+VSX_MADD(xvnmaddmsp, 4, float32, f32, NMADD_FLGS, 0, 0, 0)
+VSX_MADD(xvnmsubasp, 4, float32, f32, NMSUB_FLGS, 1, 0, 0)
+VSX_MADD(xvnmsubmsp, 4, float32, f32, NMSUB_FLGS, 0, 0, 0)
 
 #define VSX_SCALAR_CMP(op, ordered)                                      \
 void helper_##op(CPUPPCState *env, uint32_t opcode)                      \
diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index 84c6ee1..655b670 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -293,6 +293,14 @@  DEF_HELPER_2(xsdivsp, void, env, i32)
 DEF_HELPER_2(xsresp, void, env, i32)
 DEF_HELPER_2(xssqrtsp, void, env, i32)
 DEF_HELPER_2(xsrsqrtesp, void, env, i32)
+DEF_HELPER_2(xsmaddasp, void, env, i32)
+DEF_HELPER_2(xsmaddmsp, void, env, i32)
+DEF_HELPER_2(xsmsubasp, void, env, i32)
+DEF_HELPER_2(xsmsubmsp, void, env, i32)
+DEF_HELPER_2(xsnmaddasp, void, env, i32)
+DEF_HELPER_2(xsnmaddmsp, void, env, i32)
+DEF_HELPER_2(xsnmsubasp, void, env, i32)
+DEF_HELPER_2(xsnmsubmsp, void, env, i32)
 
 DEF_HELPER_2(xvadddp, void, env, i32)
 DEF_HELPER_2(xvsubdp, void, env, i32)
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index ae80289..672cf0a 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -7348,6 +7348,14 @@  GEN_VSX_HELPER_2(xsdivsp, 0x00, 0x03, 0, PPC2_VSX207)
 GEN_VSX_HELPER_2(xsresp, 0x14, 0x01, 0, PPC2_VSX207)
 GEN_VSX_HELPER_2(xssqrtsp, 0x16, 0x00, 0, PPC2_VSX207)
 GEN_VSX_HELPER_2(xsrsqrtesp, 0x14, 0x00, 0, PPC2_VSX207)
+GEN_VSX_HELPER_2(xsmaddasp, 0x04, 0x00, 0, PPC2_VSX207)
+GEN_VSX_HELPER_2(xsmaddmsp, 0x04, 0x01, 0, PPC2_VSX207)
+GEN_VSX_HELPER_2(xsmsubasp, 0x04, 0x02, 0, PPC2_VSX207)
+GEN_VSX_HELPER_2(xsmsubmsp, 0x04, 0x03, 0, PPC2_VSX207)
+GEN_VSX_HELPER_2(xsnmaddasp, 0x04, 0x10, 0, PPC2_VSX207)
+GEN_VSX_HELPER_2(xsnmaddmsp, 0x04, 0x11, 0, PPC2_VSX207)
+GEN_VSX_HELPER_2(xsnmsubasp, 0x04, 0x12, 0, PPC2_VSX207)
+GEN_VSX_HELPER_2(xsnmsubmsp, 0x04, 0x13, 0, PPC2_VSX207)
 
 GEN_VSX_HELPER_2(xvadddp, 0x00, 0x0C, 0, PPC2_VSX)
 GEN_VSX_HELPER_2(xvsubdp, 0x00, 0x0D, 0, PPC2_VSX)
@@ -10163,6 +10171,14 @@  GEN_XX3FORM(xsdivsp, 0x00, 0x03, PPC2_VSX207),
 GEN_XX2FORM(xsresp,  0x14, 0x01, PPC2_VSX207),
 GEN_XX2FORM(xssqrtsp,  0x16, 0x00, PPC2_VSX207),
 GEN_XX2FORM(xsrsqrtesp,  0x14, 0x00, PPC2_VSX207),
+GEN_XX3FORM(xsmaddasp, 0x04, 0x00, PPC2_VSX207),
+GEN_XX3FORM(xsmaddmsp, 0x04, 0x01, PPC2_VSX207),
+GEN_XX3FORM(xsmsubasp, 0x04, 0x02, PPC2_VSX207),
+GEN_XX3FORM(xsmsubmsp, 0x04, 0x03, PPC2_VSX207),
+GEN_XX3FORM(xsnmaddasp, 0x04, 0x10, PPC2_VSX207),
+GEN_XX3FORM(xsnmaddmsp, 0x04, 0x11, PPC2_VSX207),
+GEN_XX3FORM(xsnmsubasp, 0x04, 0x12, PPC2_VSX207),
+GEN_XX3FORM(xsnmsubmsp, 0x04, 0x13, PPC2_VSX207),
 
 GEN_XX3FORM(xvadddp, 0x00, 0x0C, PPC2_VSX),
 GEN_XX3FORM(xvsubdp, 0x00, 0x0D, PPC2_VSX),