target-arm: convert add_cc and sub_cc helpers to TCG

Now that the setcond TCG op is available, it's possible to replace
add_cc and sub_cc helpers by TCG code. The code generated by TCG is
actually very close to the one generated by GCC for the helper, and
this avoid all the consequences of using an helper: globals saved back
to memory, no possible optimization, call overhead, etc.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 48 insertions, 40 deletions

diff --git a/target-arm/helper.h b/target-arm/helper.h
index afdb2b5..7151e28 100644
--- a/target-arm/helper.h
+++ b/target-arm/helper.h
@@ -142,9 +142,7 @@ DEF_HELPER_2(recpe_u32, i32, i32, env)
 DEF_HELPER_2(rsqrte_u32, i32, i32, env)
 DEF_HELPER_5(neon_tbl, i32, env, i32, i32, i32, i32)
 
-DEF_HELPER_3(add_cc, i32, env, i32, i32)
 DEF_HELPER_3(adc_cc, i32, env, i32, i32)
-DEF_HELPER_3(sub_cc, i32, env, i32, i32)
 DEF_HELPER_3(sbc_cc, i32, env, i32, i32)
 
 DEF_HELPER_3(shl, i32, env, i32, i32)
diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index f13fc3a..6095f24 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -323,16 +323,6 @@ uint64_t HELPER(get_cp_reg64)(CPUARMState *env, void *rip)
    The only way to do that in TCG is a conditional branch, which clobbers
    all our temporaries.  For now implement these as helper functions.  */
 
-uint32_t HELPER (add_cc)(CPUARMState *env, uint32_t a, uint32_t b)
-{
-    uint32_t result;
-    result = a + b;
-    env->NF = env->ZF = result;
-    env->CF = result < a;
-    env->VF = (a ^ b ^ -1) & (a ^ result);
-    return result;
-}
-
 uint32_t HELPER(adc_cc)(CPUARMState *env, uint32_t a, uint32_t b)
 {
     uint32_t result;
@@ -348,16 +338,6 @@ uint32_t HELPER(adc_cc)(CPUARMState *env, uint32_t a, uint32_t b)
     return result;
 }
 
-uint32_t HELPER(sub_cc)(CPUARMState *env, uint32_t a, uint32_t b)
-{
-    uint32_t result;
-    result = a - b;
-    env->NF = env->ZF = result;
-    env->CF = a >= b;
-    env->VF = (a ^ b) & (a ^ result);
-    return result;
-}
-
 uint32_t HELPER(sbc_cc)(CPUARMState *env, uint32_t a, uint32_t b)
 {
     uint32_t result;
diff --git a/target-arm/translate.c b/target-arm/translate.c
index 1055931..da3246a 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -410,6 +410,36 @@ static void gen_sub_carry(TCGv dest, TCGv t0, TCGv t1)
     tcg_gen_subi_i32(dest, dest, 1);
 }
 
+/* dest = T0 + T1. Compute C, N, V and Z flags */
+static void gen_add_CC(TCGv dest, TCGv t0, TCGv t1)
+{
+    TCGv tmp;
+    tcg_gen_add_i32(cpu_NF, t0, t1);
+    tcg_gen_mov_i32(cpu_ZF, cpu_NF);
+    tcg_gen_setcond_i32(TCG_COND_LTU, cpu_CF, cpu_NF, t0);
+    tcg_gen_xor_i32(cpu_VF, cpu_NF, t0);
+    tmp = tcg_temp_new_i32();
+    tcg_gen_xor_i32(tmp, t0, t1);
+    tcg_gen_andc_i32(cpu_VF, cpu_VF, tmp);
+    tcg_temp_free_i32(tmp);
+    tcg_gen_mov_i32(dest, cpu_NF);
+}
+
+/* dest = T0 - T1. Compute C, N, V and Z flags */
+static void gen_sub_CC(TCGv dest, TCGv t0, TCGv t1)
+{
+    TCGv tmp;
+    tcg_gen_sub_i32(cpu_NF, t0, t1);
+    tcg_gen_mov_i32(cpu_ZF, cpu_NF);
+    tcg_gen_setcond_i32(TCG_COND_GEU, cpu_CF, t0, t1);
+    tcg_gen_xor_i32(cpu_VF, cpu_NF, t0);
+    tmp = tcg_temp_new_i32();
+    tcg_gen_xor_i32(tmp, t0, t1);
+    tcg_gen_and_i32(cpu_VF, cpu_VF, tmp);
+    tcg_temp_free_i32(tmp);
+    tcg_gen_mov_i32(dest, cpu_NF);
+}
+
 /* FIXME:  Implement this natively.  */
 #define tcg_gen_abs_i32(t0, t1) gen_helper_abs(t0, t1)
 
@@ -6970,11 +7000,11 @@ static void disas_arm_insn(CPUARMState * env, DisasContext *s)
                 if (IS_USER(s)) {
                     goto illegal_op;
                 }
-                gen_helper_sub_cc(tmp, cpu_env, tmp, tmp2);
+                gen_sub_CC(tmp, tmp, tmp2);
                 gen_exception_return(s, tmp);
             } else {
                 if (set_cc) {
-                    gen_helper_sub_cc(tmp, cpu_env, tmp, tmp2);
+                    gen_sub_CC(tmp, tmp, tmp2);
                 } else {
                     tcg_gen_sub_i32(tmp, tmp, tmp2);
                 }
@@ -6983,7 +7013,7 @@ static void disas_arm_insn(CPUARMState * env, DisasContext *s)
             break;
         case 0x03:
             if (set_cc) {
-                gen_helper_sub_cc(tmp, cpu_env, tmp2, tmp);
+                gen_sub_CC(tmp, tmp2, tmp);
             } else {
                 tcg_gen_sub_i32(tmp, tmp2, tmp);
             }
@@ -6991,7 +7021,7 @@ static void disas_arm_insn(CPUARMState * env, DisasContext *s)
             break;
         case 0x04:
             if (set_cc) {
-                gen_helper_add_cc(tmp, cpu_env, tmp, tmp2);
+                gen_add_CC(tmp, tmp, tmp2);
             } else {
                 tcg_gen_add_i32(tmp, tmp, tmp2);
             }
@@ -7037,13 +7067,13 @@ static void disas_arm_insn(CPUARMState * env, DisasContext *s)
             break;
         case 0x0a:
             if (set_cc) {
-                gen_helper_sub_cc(tmp, cpu_env, tmp, tmp2);
+                gen_sub_CC(tmp, tmp, tmp2);
             }
             tcg_temp_free_i32(tmp);
             break;
         case 0x0b:
             if (set_cc) {
-                gen_helper_add_cc(tmp, cpu_env, tmp, tmp2);
+                gen_add_CC(tmp, tmp, tmp2);
             }
             tcg_temp_free_i32(tmp);
             break;
@@ -7830,7 +7860,7 @@ gen_thumb2_data_op(DisasContext *s, int op, int conds, uint32_t shifter_out, TCG
         break;
     case 8: /* add */
         if (conds)
-            gen_helper_add_cc(t0, cpu_env, t0, t1);
+            gen_add_CC(t0, t0, t1);
         else
             tcg_gen_add_i32(t0, t0, t1);
         break;
@@ -7848,13 +7878,13 @@ gen_thumb2_data_op(DisasContext *s, int op, int conds, uint32_t shifter_out, TCG
         break;
     case 13: /* sub */
         if (conds)
-            gen_helper_sub_cc(t0, cpu_env, t0, t1);
+            gen_sub_CC(t0, t0, t1);
         else
             tcg_gen_sub_i32(t0, t0, t1);
         break;
     case 14: /* rsb */
         if (conds)
-            gen_helper_sub_cc(t0, cpu_env, t1, t0);
+            gen_sub_CC(t0, t1, t0);
         else
             tcg_gen_sub_i32(t0, t1, t0);
         break;
@@ -8982,12 +9012,12 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s)
                 if (s->condexec_mask)
                     tcg_gen_sub_i32(tmp, tmp, tmp2);
                 else
-                    gen_helper_sub_cc(tmp, cpu_env, tmp, tmp2);
+                    gen_sub_CC(tmp, tmp, tmp2);
             } else {
                 if (s->condexec_mask)
                     tcg_gen_add_i32(tmp, tmp, tmp2);
                 else
-                    gen_helper_add_cc(tmp, cpu_env, tmp, tmp2);
+                    gen_add_CC(tmp, tmp, tmp2);
             }
             tcg_temp_free_i32(tmp2);
             store_reg(s, rd, tmp);
@@ -9018,7 +9048,7 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s)
             tcg_gen_movi_i32(tmp2, insn & 0xff);
             switch (op) {
             case 1: /* cmp */
-                gen_helper_sub_cc(tmp, cpu_env, tmp, tmp2);
+                gen_sub_CC(tmp, tmp, tmp2);
                 tcg_temp_free_i32(tmp);
                 tcg_temp_free_i32(tmp2);
                 break;
@@ -9026,7 +9056,7 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s)
                 if (s->condexec_mask)
                     tcg_gen_add_i32(tmp, tmp, tmp2);
                 else
-                    gen_helper_add_cc(tmp, cpu_env, tmp, tmp2);
+                    gen_add_CC(tmp, tmp, tmp2);
                 tcg_temp_free_i32(tmp2);
                 store_reg(s, rd, tmp);
                 break;
@@ -9034,7 +9064,7 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s)
                 if (s->condexec_mask)
                     tcg_gen_sub_i32(tmp, tmp, tmp2);
                 else
-                    gen_helper_sub_cc(tmp, cpu_env, tmp, tmp2);
+                    gen_sub_CC(tmp, tmp, tmp2);
                 tcg_temp_free_i32(tmp2);
                 store_reg(s, rd, tmp);
                 break;
@@ -9070,7 +9100,7 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s)
             case 1: /* cmp */
                 tmp = load_reg(s, rd);
                 tmp2 = load_reg(s, rm);
-                gen_helper_sub_cc(tmp, cpu_env, tmp, tmp2);
+                gen_sub_CC(tmp, tmp, tmp2);
                 tcg_temp_free_i32(tmp2);
                 tcg_temp_free_i32(tmp);
                 break;
@@ -9183,14 +9213,14 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s)
             if (s->condexec_mask)
                 tcg_gen_neg_i32(tmp, tmp2);
             else
-                gen_helper_sub_cc(tmp, cpu_env, tmp, tmp2);
+                gen_sub_CC(tmp, tmp, tmp2);
             break;
         case 0xa: /* cmp */
-            gen_helper_sub_cc(tmp, cpu_env, tmp, tmp2);
+            gen_sub_CC(tmp, tmp, tmp2);
             rd = 16;
             break;
         case 0xb: /* cmn */
-            gen_helper_add_cc(tmp, cpu_env, tmp, tmp2);
+            gen_add_CC(tmp, tmp, tmp2);
             rd = 16;
             break;
         case 0xc: /* orr */