[15/67] target/arm: Convert Saturating addition and subtraction

Message ID 20190726175032.6769-16-richard.henderson@linaro.org
State New
Headers show
Series
  • target/arm: Convert aa32 base isa to decodetree
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Commit Message

Richard Henderson July 26, 2019, 5:49 p.m.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 target/arm/helper.h    |  1 -
 target/arm/op_helper.c | 15 ---------
 target/arm/translate.c | 74 +++++++++++++++++++++++++++---------------
 target/arm/a32.decode  | 10 ++++++
 target/arm/t32.decode  |  9 +++++
 5 files changed, 66 insertions(+), 43 deletions(-)

-- 
2.17.1

Comments

Peter Maydell Aug. 5, 2019, 3:40 p.m. | #1
On Fri, 26 Jul 2019 at 18:50, Richard Henderson
<richard.henderson@linaro.org> wrote:
>

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  target/arm/helper.h    |  1 -

>  target/arm/op_helper.c | 15 ---------

>  target/arm/translate.c | 74 +++++++++++++++++++++++++++---------------

>  target/arm/a32.decode  | 10 ++++++

>  target/arm/t32.decode  |  9 +++++

>  5 files changed, 66 insertions(+), 43 deletions(-)

>

> +/*

> + * Saturating addition and subtraction

> + */

> +

> +static bool op_qaddsub(DisasContext *s, arg_rrr *a, bool add, bool doub)

> +{

> +    TCGv_i32 t0, t1;

> +

> +    if (s->thumb

> +        ? !arm_dc_feature(s, ARM_FEATURE_THUMB_DSP)

> +        : !ENABLE_ARCH_5TE) {

> +        return false;

> +    }

> +

> +    t0 = load_reg(s, a->rm);

> +    t1 = load_reg(s, a->rn);

> +    if (doub) {

> +        gen_helper_add_saturate(t1, cpu_env, t1, t1);

> +    }

> +    if (add) {

> +        gen_helper_add_saturate(t0, cpu_env, t0, t1);

> +    } else {

> +        gen_helper_sub_saturate(t0, cpu_env, t0, t1);

> +    }

> +    tcg_temp_free_i32(t1);

> +    store_reg(s, a->rd, t0);

> +    return true;

> +}

> +


> -        case 0x5: /* saturating add/subtract */

> -            ARCH(5TE);

> -            rd = (insn >> 12) & 0xf;

> -            rn = (insn >> 16) & 0xf;

> -            tmp = load_reg(s, rm);

> -            tmp2 = load_reg(s, rn);

> -            if (op1 & 2)

> -                gen_helper_double_saturate(tmp2, cpu_env, tmp2);

> -            if (op1 & 1)

> -                gen_helper_sub_saturate(tmp, cpu_env, tmp, tmp2);

> -            else

> -                gen_helper_add_saturate(tmp, cpu_env, tmp, tmp2);

> -            tcg_temp_free_i32(tmp2);

> -            store_reg(s, rd, tmp);

> -            break;


This is changing the way we generate code in the middle
of also doing the refactoring. Could you not do this,
please (or where it really does make sense to do it then
call it out in the commit message)? It makes it harder
to review because now I have to read the patch for two
different changes at once...

thanks
-- PMM

Patch

diff --git a/target/arm/helper.h b/target/arm/helper.h
index 132aa1682e..1fb2cb5a77 100644
--- a/target/arm/helper.h
+++ b/target/arm/helper.h
@@ -6,7 +6,6 @@  DEF_HELPER_3(add_saturate, i32, env, i32, i32)
 DEF_HELPER_3(sub_saturate, i32, env, i32, i32)
 DEF_HELPER_3(add_usaturate, i32, env, i32, i32)
 DEF_HELPER_3(sub_usaturate, i32, env, i32, i32)
-DEF_HELPER_2(double_saturate, i32, env, s32)
 DEF_HELPER_FLAGS_2(sdiv, TCG_CALL_NO_RWG_SE, s32, s32, s32)
 DEF_HELPER_FLAGS_2(udiv, TCG_CALL_NO_RWG_SE, i32, i32, i32)
 DEF_HELPER_FLAGS_1(rbit, TCG_CALL_NO_RWG_SE, i32, i32)
diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c
index 1ab91f915e..142239b03a 100644
--- a/target/arm/op_helper.c
+++ b/target/arm/op_helper.c
@@ -135,21 +135,6 @@  uint32_t HELPER(sub_saturate)(CPUARMState *env, uint32_t a, uint32_t b)
     return res;
 }
 
-uint32_t HELPER(double_saturate)(CPUARMState *env, int32_t val)
-{
-    uint32_t res;
-    if (val >= 0x40000000) {
-        res = ~SIGNBIT;
-        env->QF = 1;
-    } else if (val <= (int32_t)0xc0000000) {
-        res = SIGNBIT;
-        env->QF = 1;
-    } else {
-        res = val << 1;
-    }
-    return res;
-}
-
 uint32_t HELPER(add_usaturate)(CPUARMState *env, uint32_t a, uint32_t b)
 {
     uint32_t res = a + b;
diff --git a/target/arm/translate.c b/target/arm/translate.c
index 354a52d36c..85f829c1bb 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -8174,6 +8174,47 @@  static bool trans_UMAAL(DisasContext *s, arg_UMAAL *a)
     return true;
 }
 
+/*
+ * Saturating addition and subtraction
+ */
+
+static bool op_qaddsub(DisasContext *s, arg_rrr *a, bool add, bool doub)
+{
+    TCGv_i32 t0, t1;
+
+    if (s->thumb
+        ? !arm_dc_feature(s, ARM_FEATURE_THUMB_DSP)
+        : !ENABLE_ARCH_5TE) {
+        return false;
+    }
+
+    t0 = load_reg(s, a->rm);
+    t1 = load_reg(s, a->rn);
+    if (doub) {
+        gen_helper_add_saturate(t1, cpu_env, t1, t1);
+    }
+    if (add) {
+        gen_helper_add_saturate(t0, cpu_env, t0, t1);
+    } else {
+        gen_helper_sub_saturate(t0, cpu_env, t0, t1);
+    }
+    tcg_temp_free_i32(t1);
+    store_reg(s, a->rd, t0);
+    return true;
+}
+
+#define DO_QADDSUB(NAME, ADD, DOUB) \
+static bool trans_##NAME(DisasContext *s, arg_rrr *a)    \
+{                                                        \
+    return op_qaddsub(s, a, ADD, DOUB);                  \
+}
+
+DO_QADDSUB(QADD, true, false)
+DO_QADDSUB(QSUB, false, false)
+DO_QADDSUB(QDADD, true, true)
+DO_QADDSUB(QDSUB, false, true)
+
+#undef DO_QADDSUB
 
 /*
  * Legacy decoder.
@@ -8582,21 +8623,10 @@  static void disas_arm_insn(DisasContext *s, unsigned int insn)
             store_reg(s, rd, tmp);
             break;
         }
-        case 0x5: /* saturating add/subtract */
-            ARCH(5TE);
-            rd = (insn >> 12) & 0xf;
-            rn = (insn >> 16) & 0xf;
-            tmp = load_reg(s, rm);
-            tmp2 = load_reg(s, rn);
-            if (op1 & 2)
-                gen_helper_double_saturate(tmp2, cpu_env, tmp2);
-            if (op1 & 1)
-                gen_helper_sub_saturate(tmp, cpu_env, tmp, tmp2);
-            else
-                gen_helper_add_saturate(tmp, cpu_env, tmp, tmp2);
-            tcg_temp_free_i32(tmp2);
-            store_reg(s, rd, tmp);
-            break;
+        case 0x5:
+            /* Saturating addition and subtraction.  */
+            /* All done in decodetree.  Reach here for illegal ops.  */
+            goto illegal_op;
         case 0x6: /* ERET */
             if (op1 != 3) {
                 goto illegal_op;
@@ -10070,18 +10100,8 @@  static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
             op = ((insn >> 17) & 0x38) | ((insn >> 4) & 7);
             if (op < 4) {
                 /* Saturating add/subtract.  */
-                if (!arm_dc_feature(s, ARM_FEATURE_THUMB_DSP)) {
-                    goto illegal_op;
-                }
-                tmp = load_reg(s, rn);
-                tmp2 = load_reg(s, rm);
-                if (op & 1)
-                    gen_helper_double_saturate(tmp, cpu_env, tmp);
-                if (op & 2)
-                    gen_helper_sub_saturate(tmp, cpu_env, tmp2, tmp);
-                else
-                    gen_helper_add_saturate(tmp, cpu_env, tmp, tmp2);
-                tcg_temp_free_i32(tmp2);
+                /* All done in decodetree.  Reach here for illegal ops.  */
+                goto illegal_op;
             } else {
                 switch (op) {
                 case 0x0a: /* rbit */
diff --git a/target/arm/a32.decode b/target/arm/a32.decode
index 71846b79fd..af6712a9e8 100644
--- a/target/arm/a32.decode
+++ b/target/arm/a32.decode
@@ -27,6 +27,7 @@ 
 &s_rri_rot       s rn rd imm rot
 &s_rrrr          s rd rn rm ra
 &rrrr            rd rn rm ra
+&rrr             rd rn rm
 
 # Data-processing (register)
 
@@ -122,3 +123,12 @@  UMULL            .... 0000 100 . .... .... .... 1001 ....     @s_rdamn
 UMLAL            .... 0000 101 . .... .... .... 1001 ....     @s_rdamn
 SMULL            .... 0000 110 . .... .... .... 1001 ....     @s_rdamn
 SMLAL            .... 0000 111 . .... .... .... 1001 ....     @s_rdamn
+
+# Saturating addition and subtraction
+
+@rndm            ---- .... .... rn:4 rd:4 .... .... rm:4      &rrr
+
+QADD             .... 0001 0000 .... .... 0000 0101 ....      @rndm
+QSUB             .... 0001 0010 .... .... 0000 0101 ....      @rndm
+QDADD            .... 0001 0100 .... .... 0000 0101 ....      @rndm
+QDSUB            .... 0001 0110 .... .... 0000 0101 ....      @rndm
diff --git a/target/arm/t32.decode b/target/arm/t32.decode
index 8e301ed2a1..7a27b5cc5c 100644
--- a/target/arm/t32.decode
+++ b/target/arm/t32.decode
@@ -24,6 +24,7 @@ 
 &s_rri_rot       !extern s rn rd imm rot
 &s_rrrr          !extern s rd rn rm ra
 &rrrr            !extern rd rn rm ra
+&rrr             !extern rd rn rm
 
 # Data-processing (register-shifted register)
 
@@ -117,6 +118,7 @@  RSB_rri          1111 0.0 1110 . .... 0 ... .... ........     @s_rri_rot
 @s0_rnadm        .... .... .... rn:4 ra:4 rd:4 .... rm:4      &s_rrrr s=0
 @s0_rn0dm        .... .... .... rn:4 .... rd:4 .... rm:4      &s_rrrr ra=0 s=0
 @rnadm           .... .... .... rn:4 ra:4 rd:4 .... rm:4      &rrrr
+@rndm            .... .... .... rn:4 .... rd:4 .... rm:4      &rrr
 
 {
   MUL            1111 1011 0000 .... 1111 .... 0000 ....      @s0_rn0dm
@@ -128,3 +130,10 @@  UMULL            1111 1011 1010 .... .... .... 0000 ....      @s0_rnadm
 SMLAL            1111 1011 1100 .... .... .... 0000 ....      @s0_rnadm
 UMLAL            1111 1011 1110 .... .... .... 0000 ....      @s0_rnadm
 UMAAL            1111 1011 1110 .... .... .... 0110 ....      @rnadm
+
+# Data-processing (two source registers)
+
+QADD             1111 1010 1000 .... 1111 .... 1000 ....      @rndm
+QSUB             1111 1010 1000 .... 1111 .... 1010 ....      @rndm
+QDADD            1111 1010 1000 .... 1111 .... 1001 ....      @rndm
+QDSUB            1111 1010 1000 .... 1111 .... 1011 ....      @rndm