[PULL 2/2] target/m68k: implement opcode fetoxm1

[Laurent Vivier <laurent@vivier.eu>]

Example provided in the launchpad bug fails with:

   qemu: uncaught target signal 4 (Illegal instruction) - core dumped
   Illegal instruction (core dumped)

It appears fetoxm1 is not implemented:

   IN: expm1f
   0x800005cc: fetoxm1x %fp2,%fp0
   Disassembler disagrees with translator over instruction decoding
   Please report this to qemu-devel@nongnu.org

   (gdb) x/2hx 0x800005cc
   0x800005cc: 0xf200 0x0808

This patch adds the instruction.

Bug: https://bugs.launchpad.net/qemu/+bug/1881450
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200531131951.631902-1-laurent@vivier.eu>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 target/m68k/helper.h     | 1 +
 target/m68k/fpu_helper.c | 5 +++++
 target/m68k/translate.c  | 3 +++
 3 files changed, 9 insertions(+)

diff --git a/target/m68k/helper.h b/target/m68k/helper.h
index feee7be62655..77808497a95c 100644
--- a/target/m68k/helper.h
+++ b/target/m68k/helper.h
@@ -83,6 +83,7 @@ DEF_HELPER_3(fatan, void, env, fp, fp)
 DEF_HELPER_3(fasin, void, env, fp, fp)
 DEF_HELPER_3(facos, void, env, fp, fp)
 DEF_HELPER_3(fatanh, void, env, fp, fp)
+DEF_HELPER_3(fetoxm1, void, env, fp, fp)
 DEF_HELPER_3(ftanh, void, env, fp, fp)
 DEF_HELPER_3(fsinh, void, env, fp, fp)
 DEF_HELPER_3(fcosh, void, env, fp, fp)
diff --git a/target/m68k/fpu_helper.c b/target/m68k/fpu_helper.c
index 36e6c704d1d0..9acf60dfd443 100644
--- a/target/m68k/fpu_helper.c
+++ b/target/m68k/fpu_helper.c
@@ -641,6 +641,11 @@ void HELPER(fatanh)(CPUM68KState *env, FPReg *res, FPReg *val)
     res->d = floatx80_atanh(val->d, &env->fp_status);
 }
 
+void HELPER(fetoxm1)(CPUM68KState *env, FPReg *res, FPReg *val)
+{
+    res->d = floatx80_etoxm1(val->d, &env->fp_status);
+}
+
 void HELPER(ftanh)(CPUM68KState *env, FPReg *res, FPReg *val)
 {
     res->d = floatx80_tanh(val->d, &env->fp_status);
diff --git a/target/m68k/translate.c b/target/m68k/translate.c
index c093f6c683e8..3fc67aa45261 100644
--- a/target/m68k/translate.c
+++ b/target/m68k/translate.c
@@ -5160,6 +5160,9 @@ DISAS_INSN(fpu)
     case 0x06: /* flognp1 */
         gen_helper_flognp1(cpu_env, cpu_dest, cpu_src);
         break;
+    case 0x08: /* fetoxm1 */
+        gen_helper_fetoxm1(cpu_env, cpu_dest, cpu_src);
+        break;
     case 0x09: /* ftanh */
         gen_helper_ftanh(cpu_env, cpu_dest, cpu_src);
         break;
-- 
2.26.2