target/sh4: do not check for PR bit for fabs instruction

The SH4 manual is not fully clear about that, but real hardware do not
check for the PR bit, which allows to select between single or double
precision, for the fabs instruction. This is probably what is meant by
"Same operation is performed regardless of precision."

Remove the check, and at the same time use a TCG instruction instead of
a helper to clear one bit.

LP: https://bugs.launchpad.net/qemu/+bug/1701821
Reported-by: Bruno Haible <bruno@clisp.org>
Message-Id: <20170702202814.27793-2-aurelien@aurel32.net>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

diff --git a/target/sh4/helper.h b/target/sh4/helper.h
index dce859caeacea1dd70d4bd82c45ee4d9c8b051b4..f71522482293d7738c7d29ccb133212aca75c24a 100644 (file)
--- a/target/sh4/helper.h
+++ b/target/sh4/helper.h
@@ -16,8 +16,6 @@ DEF_HELPER_3(macw, void, env, i32, i32)
 
 DEF_HELPER_2(ld_fpscr, void, env, i32)
 
-DEF_HELPER_FLAGS_1(fabs_FT, TCG_CALL_NO_RWG_SE, f32, f32)
-DEF_HELPER_FLAGS_1(fabs_DT, TCG_CALL_NO_RWG_SE, f64, f64)
 DEF_HELPER_FLAGS_3(fadd_FT, TCG_CALL_NO_WG, f32, env, f32, f32)
 DEF_HELPER_FLAGS_3(fadd_DT, TCG_CALL_NO_WG, f64, env, f64, f64)
 DEF_HELPER_FLAGS_2(fcnvsd_FT_DT, TCG_CALL_NO_WG, f64, env, f32)

diff --git a/target/sh4/op_helper.c b/target/sh4/op_helper.c
index 528a40ac1d3a6257e50872a69593eb0b518ca737..5e3a3ba68caa48c65364795135689b5e9fbb8c21 100644 (file)
--- a/target/sh4/op_helper.c
+++ b/target/sh4/op_helper.c
@@ -252,16 +252,6 @@ static void update_fpscr(CPUSH4State *env, uintptr_t retaddr)
     }
 }
 
-float32 helper_fabs_FT(float32 t0)
-{
-    return float32_abs(t0);
-}
-
-float64 helper_fabs_DT(float64 t0)
-{
-    return float64_abs(t0);
-}
-
 float32 helper_fadd_FT(CPUSH4State *env, float32 t0, float32 t1)
 {
     set_float_exception_flags(0, &env->fp_status);

diff --git a/target/sh4/translate.c b/target/sh4/translate.c
index 8bc132b27b9a3b73f762d8eb1a55fc3c37ddeab0..bff212a78eefc00a6268b6115ccf46c7f01691f0 100644 (file)
--- a/target/sh4/translate.c
+++ b/target/sh4/translate.c
@@ -1695,19 +1695,10 @@ static void _decode_opc(DisasContext * ctx)
            gen_helper_fneg_T(cpu_fregs[FREG(B11_8)], cpu_fregs[FREG(B11_8)]);
        }
        return;
-    case 0xf05d: /* fabs FRn/DRn */
+    case 0xf05d: /* fabs FRn/DRn - FPCSR: Nothing */
        CHECK_FPU_ENABLED
-        if (ctx->tbflags & FPSCR_PR) {
-           if (ctx->opcode & 0x0100)
-               break; /* illegal instruction */
-           TCGv_i64 fp = tcg_temp_new_i64();
-           gen_load_fpr64(fp, DREG(B11_8));
-           gen_helper_fabs_DT(fp, fp);
-           gen_store_fpr64(fp, DREG(B11_8));
-           tcg_temp_free_i64(fp);
-       } else {
-           gen_helper_fabs_FT(cpu_fregs[FREG(B11_8)], cpu_fregs[FREG(B11_8)]);
-       }
+        tcg_gen_andi_i32(cpu_fregs[FREG(B11_8)], cpu_fregs[FREG(B11_8)],
+                         0x7fffffff);
        return;
     case 0xf06d: /* fsqrt FRn */
        CHECK_FPU_ENABLED