[Qemu-devel] [PATCH v2 40/42] target/arm: Convert VCVT fp/fixed-point conversion insns to decodetree

[Peter Maydell <peter.maydell@linaro.org>]

Convert the VCVT (between floating-point and fixed-point) instructions
to decodetree.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/translate-vfp.inc.c | 124 +++++++++++++++++++++++++++++++++
 target/arm/translate.c         |  57 +--------------
 target/arm/vfp.decode          |  10 +++
 3 files changed, 136 insertions(+), 55 deletions(-)

diff --git a/target/arm/translate-vfp.inc.c b/target/arm/translate-vfp.inc.c
index 161f0fdd888..db07fdd8736 100644
--- a/target/arm/translate-vfp.inc.c
+++ b/target/arm/translate-vfp.inc.c
@@ -2454,3 +2454,127 @@ static bool trans_VJCVT(DisasContext *s, arg_VJCVT *a)
     tcg_temp_free_i32(vd);
     return true;
 }
+
+static bool trans_VCVT_fix_sp(DisasContext *s, arg_VCVT_fix_sp *a)
+{
+    TCGv_i32 vd, shift;
+    TCGv_ptr fpst;
+    int frac_bits;
+
+    if (!arm_dc_feature(s, ARM_FEATURE_VFP3)) {
+        return false;
+    }
+
+    if (!vfp_access_check(s)) {
+        return true;
+    }
+
+    frac_bits = (a->opc & 1) ? (32 - a->imm) : (16 - a->imm);
+
+    vd = tcg_temp_new_i32();
+    neon_load_reg32(vd, a->vd);
+
+    fpst = get_fpstatus_ptr(false);
+    shift = tcg_const_i32(frac_bits);
+
+    /* Switch on op:U:sx bits */
+    switch (a->opc) {
+    case 0:
+        gen_helper_vfp_shtos(vd, vd, shift, fpst);
+        break;
+    case 1:
+        gen_helper_vfp_sltos(vd, vd, shift, fpst);
+        break;
+    case 2:
+        gen_helper_vfp_uhtos(vd, vd, shift, fpst);
+        break;
+    case 3:
+        gen_helper_vfp_ultos(vd, vd, shift, fpst);
+        break;
+    case 4:
+        gen_helper_vfp_toshs_round_to_zero(vd, vd, shift, fpst);
+        break;
+    case 5:
+        gen_helper_vfp_tosls_round_to_zero(vd, vd, shift, fpst);
+        break;
+    case 6:
+        gen_helper_vfp_touhs_round_to_zero(vd, vd, shift, fpst);
+        break;
+    case 7:
+        gen_helper_vfp_touls_round_to_zero(vd, vd, shift, fpst);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+
+    neon_store_reg32(vd, a->vd);
+    tcg_temp_free_i32(vd);
+    tcg_temp_free_i32(shift);
+    tcg_temp_free_ptr(fpst);
+    return true;
+}
+
+static bool trans_VCVT_fix_dp(DisasContext *s, arg_VCVT_fix_dp *a)
+{
+    TCGv_i64 vd;
+    TCGv_i32 shift;
+    TCGv_ptr fpst;
+    int frac_bits;
+
+    if (!arm_dc_feature(s, ARM_FEATURE_VFP3)) {
+        return false;
+    }
+
+    /* UNDEF accesses to D16-D31 if they don't exist. */
+    if (!dc_isar_feature(aa32_fp_d32, s) && (a->vd & 0x10)) {
+        return false;
+    }
+
+    if (!vfp_access_check(s)) {
+        return true;
+    }
+
+    frac_bits = (a->opc & 1) ? (32 - a->imm) : (16 - a->imm);
+
+    vd = tcg_temp_new_i64();
+    neon_load_reg64(vd, a->vd);
+
+    fpst = get_fpstatus_ptr(false);
+    shift = tcg_const_i32(frac_bits);
+
+    /* Switch on op:U:sx bits */
+    switch (a->opc) {
+    case 0:
+        gen_helper_vfp_shtod(vd, vd, shift, fpst);
+        break;
+    case 1:
+        gen_helper_vfp_sltod(vd, vd, shift, fpst);
+        break;
+    case 2:
+        gen_helper_vfp_uhtod(vd, vd, shift, fpst);
+        break;
+    case 3:
+        gen_helper_vfp_ultod(vd, vd, shift, fpst);
+        break;
+    case 4:
+        gen_helper_vfp_toshd_round_to_zero(vd, vd, shift, fpst);
+        break;
+    case 5:
+        gen_helper_vfp_tosld_round_to_zero(vd, vd, shift, fpst);
+        break;
+    case 6:
+        gen_helper_vfp_touhd_round_to_zero(vd, vd, shift, fpst);
+        break;
+    case 7:
+        gen_helper_vfp_tould_round_to_zero(vd, vd, shift, fpst);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+
+    neon_store_reg64(vd, a->vd);
+    tcg_temp_free_i64(vd);
+    tcg_temp_free_i32(shift);
+    tcg_temp_free_ptr(fpst);
+    return true;
+}
diff --git a/target/arm/translate.c b/target/arm/translate.c
index 99b436ad6f7..6046bb32247 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -1439,13 +1439,9 @@ static inline void gen_vfp_##name(int dp, int shift, int neon) \
     tcg_temp_free_i32(tmp_shift); \
     tcg_temp_free_ptr(statusptr); \
 }
-VFP_GEN_FIX(tosh, _round_to_zero)
 VFP_GEN_FIX(tosl, _round_to_zero)
-VFP_GEN_FIX(touh, _round_to_zero)
 VFP_GEN_FIX(toul, _round_to_zero)
-VFP_GEN_FIX(shto, )
 VFP_GEN_FIX(slto, )
-VFP_GEN_FIX(uhto, )
 VFP_GEN_FIX(ulto, )
 #undef VFP_GEN_FIX
 
@@ -3050,7 +3046,8 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn)
                 return 1;
             case 15:
                 switch (rn) {
-                case 0 ... 19:
+                case 0 ... 23:
+                case 28 ... 31:
                     /* Already handled by decodetree */
                     return 1;
                 default:
@@ -3070,21 +3067,6 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn)
                     rd_is_dp = false;
                     break;
 
-                case 0x14: /* vcvt fp <-> fixed */
-                case 0x15:
-                case 0x16:
-                case 0x17:
-                case 0x1c:
-                case 0x1d:
-                case 0x1e:
-                case 0x1f:
-                    if (!arm_dc_feature(s, ARM_FEATURE_VFP3)) {
-                        return 1;
-                    }
-                    /* Immediate frac_bits has same format as SREG_M.  */
-                    rm_is_dp = false;
-                    break;
-
                 default:
                     return 1;
                 }
@@ -3143,17 +3125,6 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn)
             /* Load the initial operands.  */
             if (op == 15) {
                 switch (rn) {
-                case 0x14: /* vcvt fp <-> fixed */
-                case 0x15:
-                case 0x16:
-                case 0x17:
-                case 0x1c:
-                case 0x1d:
-                case 0x1e:
-                case 0x1f:
-                    /* Source and destination the same.  */
-                    gen_mov_F0_vreg(dp, rd);
-                    break;
                 default:
                     /* One source operand.  */
                     gen_mov_F0_vreg(rm_is_dp, rm);
@@ -3170,18 +3141,6 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn)
                 switch (op) {
                 case 15: /* extension space */
                     switch (rn) {
-                    case 20: /* fshto */
-                        gen_vfp_shto(dp, 16 - rm, 0);
-                        break;
-                    case 21: /* fslto */
-                        gen_vfp_slto(dp, 32 - rm, 0);
-                        break;
-                    case 22: /* fuhto */
-                        gen_vfp_uhto(dp, 16 - rm, 0);
-                        break;
-                    case 23: /* fulto */
-                        gen_vfp_ulto(dp, 32 - rm, 0);
-                        break;
                     case 24: /* ftoui */
                         gen_vfp_toui(dp, 0);
                         break;
@@ -3194,18 +3153,6 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn)
                     case 27: /* ftosiz */
                         gen_vfp_tosiz(dp, 0);
                         break;
-                    case 28: /* ftosh */
-                        gen_vfp_tosh(dp, 16 - rm, 0);
-                        break;
-                    case 29: /* ftosl */
-                        gen_vfp_tosl(dp, 32 - rm, 0);
-                        break;
-                    case 30: /* ftouh */
-                        gen_vfp_touh(dp, 16 - rm, 0);
-                        break;
-                    case 31: /* ftoul */
-                        gen_vfp_toul(dp, 32 - rm, 0);
-                        break;
                     default: /* undefined */
                         g_assert_not_reached();
                     }
diff --git a/target/arm/vfp.decode b/target/arm/vfp.decode
index 1a7c9b533de..c3223a124ac 100644
--- a/target/arm/vfp.decode
+++ b/target/arm/vfp.decode
@@ -224,3 +224,13 @@ VCVT_int_dp  ---- 1110 1.11 1000 .... 1011 s:1 1.0 .... \
 # VJCVT is always dp to sp
 VJCVT        ---- 1110 1.11 1001 .... 1011 11.0 .... \
              vd=%vd_sp vm=%vm_dp
+
+# VCVT between floating-point and fixed-point. The immediate value
+# is in the same format as a Vm single-precision register number.
+# We assemble bits 18 (op), 16 (u) and 7 (sx) into a single opc field
+# for the convenience of the trans_VCVT_fix functions.
+%vcvt_fix_op 18:1 16:1 7:1
+VCVT_fix_sp  ---- 1110 1.11 1.1. .... 1010 .1.0 .... \
+             vd=%vd_sp imm=%vm_sp opc=%vcvt_fix_op
+VCVT_fix_dp  ---- 1110 1.11 1.1. .... 1011 .1.0 .... \
+             vd=%vd_dp imm=%vm_sp opc=%vcvt_fix_op
-- 
2.20.1