Merge tag 'm68k-next-pull-request' of https://github.com/vivier/qemu-m68k into staging

M68K pull request 20230116

fix FPSR quotient byte

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# gpg: Signature made Mon 16 Jan 2023 09:18:35 GMT
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* tag 'm68k-next-pull-request' of https://github.com/vivier/qemu-m68k:
  target/m68k: fix FPSR quotient byte for frem instruction
  target/m68k: fix FPSR quotient byte for fmod instruction
  target/m68k: pass sign directly into make_quotient()
  target/m68k: pass quotient directly into make_quotient()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 31 insertions, 18 deletions

diff --git a/target/m68k/fpu_helper.c b/target/m68k/fpu_helper.c
index fdc4937e29..3a37d8f584 100644
--- a/target/m68k/fpu_helper.c
+++ b/target/m68k/fpu_helper.c
@@ -515,37 +515,50 @@ uint32_t HELPER(fmovemd_ld_postinc)(CPUM68KState *env, uint32_t addr,
     return fmovem_postinc(env, addr, mask, cpu_ld_float64_ra);
 }
 
-static void make_quotient(CPUM68KState *env, floatx80 val)
+static void make_quotient(CPUM68KState *env, int sign, uint32_t quotient)
 {
-    int32_t quotient;
-    int sign;
-
-    if (floatx80_is_any_nan(val)) {
-        return;
-    }
-
-    quotient = floatx80_to_int32(val, &env->fp_status);
-    sign = quotient < 0;
-    if (sign) {
-        quotient = -quotient;
-    }
-
     quotient = (sign << 7) | (quotient & 0x7f);
     env->fpsr = (env->fpsr & ~FPSR_QT_MASK) | (quotient << FPSR_QT_SHIFT);
 }
 
 void HELPER(fmod)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
 {
-    res->d = floatx80_mod(val1->d, val0->d, &env->fp_status);
+    uint64_t quotient;
+    int sign = extractFloatx80Sign(val1->d) ^ extractFloatx80Sign(val0->d);
+
+    res->d = floatx80_modrem(val1->d, val0->d, true, &quotient,
+                             &env->fp_status);
 
-    make_quotient(env, res->d);
+    if (floatx80_is_any_nan(res->d)) {
+        return;
+    }
+
+    make_quotient(env, sign, quotient);
 }
 
 void HELPER(frem)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
 {
-    res->d = floatx80_rem(val1->d, val0->d, &env->fp_status);
+    FPReg fp_quot;
+    floatx80 fp_rem;
+
+    fp_rem = floatx80_rem(val1->d, val0->d, &env->fp_status);
+    if (!floatx80_is_any_nan(fp_rem)) {
+        float_status fp_status = { };
+        uint32_t quotient;
+        int sign;
+
+        /* Calculate quotient directly using round to nearest mode */
+        set_float_rounding_mode(float_round_nearest_even, &fp_status);
+        set_floatx80_rounding_precision(
+            get_floatx80_rounding_precision(&env->fp_status), &fp_status);
+        fp_quot.d = floatx80_div(val1->d, val0->d, &fp_status);
+
+        sign = extractFloatx80Sign(fp_quot.d);
+        quotient = floatx80_to_int32(floatx80_abs(fp_quot.d), &env->fp_status);
+        make_quotient(env, sign, quotient);
+    }
 
-    make_quotient(env, res->d);
+    res->d = fp_rem;
 }
 
 void HELPER(fgetexp)(CPUM68KState *env, FPReg *res, FPReg *val)