[Qemu-devel] [PATCH v2 11/42] target/arm: Add helpers for VFP register loads and stores

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

The current VFP code has two different idioms for
loading and storing from the VFP register file:
 1 using the gen_mov_F0_vreg() and similar functions,
   which load and store to a fixed set of TCG globals
   cpu_F0s, CPU_F0d, etc
 2 by direct calls to tcg_gen_ld_f64() and friends

We want to phase out idiom 1 (because the use of the
fixed globals is a relic of a much older version of TCG),
but idiom 2 is quite longwinded:
 tcg_gen_ld_f64(tmp, cpu_env, vfp_reg_offset(true, reg))
requires us to specify the 64-bitness twice, once in
the function name and once by passing 'true' to
vfp_reg_offset(). There's no guard against accidentally
passing the wrong flag.

Instead, let's move to a convention of accessing 64-bit
registers via the existing neon_load_reg64() and
neon_store_reg64(), and provide new neon_load_reg32()
and neon_store_reg32() for the 32-bit equivalents.

Implement the new functions and use them in the code in
translate-vfp.inc.c. We will convert the rest of the VFP
code as we do the decodetree conversion in subsequent
commits.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/translate-vfp.inc.c | 40 +++++++++++++++++-----------------
 target/arm/translate.c         | 10 +++++++++
 2 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/target/arm/translate-vfp.inc.c b/target/arm/translate-vfp.inc.c
index 2f070a6e0d9..24358f3d3eb 100644
--- a/target/arm/translate-vfp.inc.c
+++ b/target/arm/translate-vfp.inc.c
@@ -179,8 +179,8 @@ static bool trans_VSEL(DisasContext *s, arg_VSEL *a)
         tcg_gen_ext_i32_i64(nf, cpu_NF);
         tcg_gen_ext_i32_i64(vf, cpu_VF);
 
-        tcg_gen_ld_f64(frn, cpu_env, vfp_reg_offset(dp, rn));
-        tcg_gen_ld_f64(frm, cpu_env, vfp_reg_offset(dp, rm));
+        neon_load_reg64(frn, rn);
+        neon_load_reg64(frm, rm);
         switch (a->cc) {
         case 0: /* eq: Z */
             tcg_gen_movcond_i64(TCG_COND_EQ, dest, zf, zero,
@@ -207,7 +207,7 @@ static bool trans_VSEL(DisasContext *s, arg_VSEL *a)
             tcg_temp_free_i64(tmp);
             break;
         }
-        tcg_gen_st_f64(dest, cpu_env, vfp_reg_offset(dp, rd));
+        neon_store_reg64(dest, rd);
         tcg_temp_free_i64(frn);
         tcg_temp_free_i64(frm);
         tcg_temp_free_i64(dest);
@@ -226,8 +226,8 @@ static bool trans_VSEL(DisasContext *s, arg_VSEL *a)
         frn = tcg_temp_new_i32();
         frm = tcg_temp_new_i32();
         dest = tcg_temp_new_i32();
-        tcg_gen_ld_f32(frn, cpu_env, vfp_reg_offset(dp, rn));
-        tcg_gen_ld_f32(frm, cpu_env, vfp_reg_offset(dp, rm));
+        neon_load_reg32(frn, rn);
+        neon_load_reg32(frm, rm);
         switch (a->cc) {
         case 0: /* eq: Z */
             tcg_gen_movcond_i32(TCG_COND_EQ, dest, cpu_ZF, zero,
@@ -254,7 +254,7 @@ static bool trans_VSEL(DisasContext *s, arg_VSEL *a)
             tcg_temp_free_i32(tmp);
             break;
         }
-        tcg_gen_st_f32(dest, cpu_env, vfp_reg_offset(dp, rd));
+        neon_store_reg32(dest, rd);
         tcg_temp_free_i32(frn);
         tcg_temp_free_i32(frm);
         tcg_temp_free_i32(dest);
@@ -298,14 +298,14 @@ static bool trans_VMINMAXNM(DisasContext *s, arg_VMINMAXNM *a)
         frm = tcg_temp_new_i64();
         dest = tcg_temp_new_i64();
 
-        tcg_gen_ld_f64(frn, cpu_env, vfp_reg_offset(dp, rn));
-        tcg_gen_ld_f64(frm, cpu_env, vfp_reg_offset(dp, rm));
+        neon_load_reg64(frn, rn);
+        neon_load_reg64(frm, rm);
         if (vmin) {
             gen_helper_vfp_minnumd(dest, frn, frm, fpst);
         } else {
             gen_helper_vfp_maxnumd(dest, frn, frm, fpst);
         }
-        tcg_gen_st_f64(dest, cpu_env, vfp_reg_offset(dp, rd));
+        neon_store_reg64(dest, rd);
         tcg_temp_free_i64(frn);
         tcg_temp_free_i64(frm);
         tcg_temp_free_i64(dest);
@@ -316,14 +316,14 @@ static bool trans_VMINMAXNM(DisasContext *s, arg_VMINMAXNM *a)
         frm = tcg_temp_new_i32();
         dest = tcg_temp_new_i32();
 
-        tcg_gen_ld_f32(frn, cpu_env, vfp_reg_offset(dp, rn));
-        tcg_gen_ld_f32(frm, cpu_env, vfp_reg_offset(dp, rm));
+        neon_load_reg32(frn, rn);
+        neon_load_reg32(frm, rm);
         if (vmin) {
             gen_helper_vfp_minnums(dest, frn, frm, fpst);
         } else {
             gen_helper_vfp_maxnums(dest, frn, frm, fpst);
         }
-        tcg_gen_st_f32(dest, cpu_env, vfp_reg_offset(dp, rd));
+        neon_store_reg32(dest, rd);
         tcg_temp_free_i32(frn);
         tcg_temp_free_i32(frm);
         tcg_temp_free_i32(dest);
@@ -379,9 +379,9 @@ static bool trans_VRINT(DisasContext *s, arg_VRINT *a)
         TCGv_i64 tcg_res;
         tcg_op = tcg_temp_new_i64();
         tcg_res = tcg_temp_new_i64();
-        tcg_gen_ld_f64(tcg_op, cpu_env, vfp_reg_offset(dp, rm));
+        neon_load_reg64(tcg_op, rm);
         gen_helper_rintd(tcg_res, tcg_op, fpst);
-        tcg_gen_st_f64(tcg_res, cpu_env, vfp_reg_offset(dp, rd));
+        neon_store_reg64(tcg_res, rd);
         tcg_temp_free_i64(tcg_op);
         tcg_temp_free_i64(tcg_res);
     } else {
@@ -389,9 +389,9 @@ static bool trans_VRINT(DisasContext *s, arg_VRINT *a)
         TCGv_i32 tcg_res;
         tcg_op = tcg_temp_new_i32();
         tcg_res = tcg_temp_new_i32();
-        tcg_gen_ld_f32(tcg_op, cpu_env, vfp_reg_offset(dp, rm));
+        neon_load_reg32(tcg_op, rm);
         gen_helper_rints(tcg_res, tcg_op, fpst);
-        tcg_gen_st_f32(tcg_res, cpu_env, vfp_reg_offset(dp, rd));
+        neon_store_reg32(tcg_res, rd);
         tcg_temp_free_i32(tcg_op);
         tcg_temp_free_i32(tcg_res);
     }
@@ -440,14 +440,14 @@ static bool trans_VCVT(DisasContext *s, arg_VCVT *a)
         tcg_double = tcg_temp_new_i64();
         tcg_res = tcg_temp_new_i64();
         tcg_tmp = tcg_temp_new_i32();
-        tcg_gen_ld_f64(tcg_double, cpu_env, vfp_reg_offset(1, rm));
+        neon_load_reg64(tcg_double, rm);
         if (is_signed) {
             gen_helper_vfp_tosld(tcg_res, tcg_double, tcg_shift, fpst);
         } else {
             gen_helper_vfp_tould(tcg_res, tcg_double, tcg_shift, fpst);
         }
         tcg_gen_extrl_i64_i32(tcg_tmp, tcg_res);
-        tcg_gen_st_f32(tcg_tmp, cpu_env, vfp_reg_offset(0, rd));
+        neon_store_reg32(tcg_tmp, rd);
         tcg_temp_free_i32(tcg_tmp);
         tcg_temp_free_i64(tcg_res);
         tcg_temp_free_i64(tcg_double);
@@ -455,13 +455,13 @@ static bool trans_VCVT(DisasContext *s, arg_VCVT *a)
         TCGv_i32 tcg_single, tcg_res;
         tcg_single = tcg_temp_new_i32();
         tcg_res = tcg_temp_new_i32();
-        tcg_gen_ld_f32(tcg_single, cpu_env, vfp_reg_offset(0, rm));
+        neon_load_reg32(tcg_single, rm);
         if (is_signed) {
             gen_helper_vfp_tosls(tcg_res, tcg_single, tcg_shift, fpst);
         } else {
             gen_helper_vfp_touls(tcg_res, tcg_single, tcg_shift, fpst);
         }
-        tcg_gen_st_f32(tcg_res, cpu_env, vfp_reg_offset(0, rd));
+        neon_store_reg32(tcg_res, rd);
         tcg_temp_free_i32(tcg_res);
         tcg_temp_free_i32(tcg_single);
     }
diff --git a/target/arm/translate.c b/target/arm/translate.c
index e42a21d4aa5..3661ed57cd3 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -1689,6 +1689,16 @@ static inline void neon_store_reg64(TCGv_i64 var, int reg)
     tcg_gen_st_i64(var, cpu_env, vfp_reg_offset(1, reg));
 }
 
+static inline void neon_load_reg32(TCGv_i32 var, int reg)
+{
+    tcg_gen_ld_i32(var, cpu_env, vfp_reg_offset(false, reg));
+}
+
+static inline void neon_store_reg32(TCGv_i32 var, int reg)
+{
+    tcg_gen_st_i32(var, cpu_env, vfp_reg_offset(false, reg));
+}
+
 static TCGv_ptr vfp_reg_ptr(bool dp, int reg)
 {
     TCGv_ptr ret = tcg_temp_new_ptr();
-- 
2.20.1