[Qemu-devel] [PATCH v6 4/4] target-arm: Implement ARMv8 SIMD VMAXNM and VMINNM instructions.

[Will Newton <will.newton@linaro.org>]

This adds support for the ARMv8 Advanced SIMD VMAXNM and VMINNM
instructions.

Signed-off-by: Will Newton <will.newton@linaro.org>
---
 target-arm/helper.h      |  3 +++
 target-arm/neon_helper.c | 24 ++++++++++++++++++++++++
 target-arm/translate.c   | 23 +++++++++++++++++------
 3 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/target-arm/helper.h b/target-arm/helper.h
index d459a39..3ecbbd2 100644
--- a/target-arm/helper.h
+++ b/target-arm/helper.h
@@ -355,6 +355,9 @@ DEF_HELPER_3(neon_cgt_f32, i32, i32, i32, ptr)
 DEF_HELPER_3(neon_acge_f32, i32, i32, i32, ptr)
 DEF_HELPER_3(neon_acgt_f32, i32, i32, i32, ptr)

+DEF_HELPER_3(neon_maxnm_f32, i32, i32, i32, ptr)
+DEF_HELPER_3(neon_minnm_f32, i32, i32, i32, ptr)
+
 /* iwmmxt_helper.c */
 DEF_HELPER_2(iwmmxt_maddsq, i64, i64, i64)
 DEF_HELPER_2(iwmmxt_madduq, i64, i64, i64)
diff --git a/target-arm/neon_helper.c b/target-arm/neon_helper.c
index b028cc2..cc55e83 100644
--- a/target-arm/neon_helper.c
+++ b/target-arm/neon_helper.c
@@ -2008,3 +2008,27 @@ void HELPER(neon_zip16)(CPUARMState *env, uint32_t rd, uint32_t rm)
     env->vfp.regs[rm] = make_float64(m0);
     env->vfp.regs[rd] = make_float64(d0);
 }
+
+uint32_t HELPER(neon_maxnm_f32)(uint32_t a, uint32_t b, void *fpstp)
+{
+    float_status *fpst = fpstp;
+    float32 af = make_float32(a);
+    float32 bf = make_float32(b);
+    if (float32_is_quiet_nan(af) && !float32_is_quiet_nan(bf))
+        return b;
+    else if (float32_is_quiet_nan(bf) && !float32_is_quiet_nan(af))
+        return a;
+    return float32_val(float32_max(af, bf, fpst));
+}
+
+uint32_t HELPER(neon_minnm_f32)(uint32_t a, uint32_t b, void *fpstp)
+{
+    float_status *fpst = fpstp;
+    float32 af = make_float32(a);
+    float32 bf = make_float32(b);
+    if (float32_is_quiet_nan(af) && !float32_is_quiet_nan(bf))
+        return b;
+    else if (float32_is_quiet_nan(bf) && !float32_is_quiet_nan(af))
+        return a;
+    return float32_val(float32_min(af, bf, fpst));
+}
diff --git a/target-arm/translate.c b/target-arm/translate.c
index cac7668..9a4e7f4 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -4540,7 +4540,7 @@ static void gen_neon_narrow_op(int op, int u, int size,
 #define NEON_3R_FLOAT_CMP 28 /* float VCEQ, VCGE, VCGT */
 #define NEON_3R_FLOAT_ACMP 29 /* float VACGE, VACGT, VACLE, VACLT */
 #define NEON_3R_FLOAT_MINMAX 30 /* float VMIN, VMAX */
-#define NEON_3R_VRECPS_VRSQRTS 31 /* float VRECPS, VRSQRTS */
+#define NEON_3R_VRECPS_VRSQRTS 31 /* float VRECPS, VRSQRTS, VMAXNM/MINNM */

 static const uint8_t neon_3r_sizes[] = {
     [NEON_3R_VHADD] = 0x7,
@@ -4835,7 +4835,8 @@ static int disas_neon_data_insn(CPUARMState * env, DisasContext *s, uint32_t ins
             }
             break;
         case NEON_3R_VRECPS_VRSQRTS:
-            if (u) {
+            /* Encoding shared with VMAXNM/VMINNM in ARMv8 */
+            if (u && (!arm_feature(env, ARM_FEATURE_V8) || (size & 1))) {
                 return 1;
             }
             break;
@@ -5125,10 +5126,20 @@ static int disas_neon_data_insn(CPUARMState * env, DisasContext *s, uint32_t ins
             break;
         }
         case NEON_3R_VRECPS_VRSQRTS:
-            if (size == 0)
-                gen_helper_recps_f32(tmp, tmp, tmp2, cpu_env);
-            else
-                gen_helper_rsqrts_f32(tmp, tmp, tmp2, cpu_env);
+            if (u) {
+                /* VMAXNM/VMINNM */
+                TCGv_ptr fpstatus = get_fpstatus_ptr(1);
+                if (size == 0)
+                    gen_helper_neon_maxnm_f32(tmp, tmp, tmp2, fpstatus);
+                else
+                    gen_helper_neon_minnm_f32(tmp, tmp, tmp2, fpstatus);
+                tcg_temp_free_ptr(fpstatus);
+            } else {
+                if (size == 0)
+                    gen_helper_recps_f32(tmp, tmp, tmp2, cpu_env);
+                else
+                    gen_helper_rsqrts_f32(tmp, tmp, tmp2, cpu_env);
+            }
             break;
         case NEON_3R_VFM:
         {
-- 
1.8.1.4