Merge remote-tracking branch 'remotes/rth/tags/pull-fpu-20200515' into staging

floatx80 x87 pseudo-denormal fixes

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# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
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* remotes/rth/tags/pull-fpu-20200515:
  softfloat: fix floatx80 pseudo-denormal round to integer
  softfloat: fix floatx80 pseudo-denormal comparisons
  softfloat: fix floatx80 pseudo-denormal addition / subtraction
  softfloat: silence sNaN for conversions to/from floatx80

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

2 files changed, 101 insertions, 0 deletions

diff --git a/tests/tcg/i386/test-i386-pseudo-denormal.c b/tests/tcg/i386/test-i386-pseudo-denormal.c
new file mode 100644
index 0000000000..00d510cf4a
--- /dev/null
+++ b/tests/tcg/i386/test-i386-pseudo-denormal.c
@@ -0,0 +1,38 @@
+/* Test pseudo-denormal operations.  */
+
+#include <stdint.h>
+#include <stdio.h>
+
+union u {
+    struct { uint64_t sig; uint16_t sign_exp; } s;
+    long double ld;
+};
+
+volatile union u ld_pseudo_m16382 = { .s = { UINT64_C(1) << 63, 0 } };
+
+volatile long double ld_res;
+
+int main(void)
+{
+    short cw;
+    int ret = 0;
+    ld_res = ld_pseudo_m16382.ld + ld_pseudo_m16382.ld;
+    if (ld_res != 0x1p-16381L) {
+        printf("FAIL: pseudo-denormal add\n");
+        ret = 1;
+    }
+    if (ld_pseudo_m16382.ld != 0x1p-16382L) {
+        printf("FAIL: pseudo-denormal compare\n");
+        ret = 1;
+    }
+    /* Set round-upward.  */
+    __asm__ volatile ("fnstcw %0" : "=m" (cw));
+    cw = (cw & ~0xc00) | 0x800;
+    __asm__ volatile ("fldcw %0" : : "m" (cw));
+    __asm__ ("frndint" : "=t" (ld_res) : "0" (ld_pseudo_m16382.ld));
+    if (ld_res != 1.0L) {
+        printf("FAIL: pseudo-denormal round-to-integer\n");
+        ret = 1;
+    }
+    return ret;
+}
diff --git a/tests/tcg/i386/test-i386-snan-convert.c b/tests/tcg/i386/test-i386-snan-convert.c
new file mode 100644
index 0000000000..ed6d535ce2
--- /dev/null
+++ b/tests/tcg/i386/test-i386-snan-convert.c
@@ -0,0 +1,63 @@
+/* Test conversions of signaling NaNs to and from long double.  */
+
+#include <stdint.h>
+#include <stdio.h>
+
+volatile float f_res;
+volatile double d_res;
+volatile long double ld_res;
+
+volatile float f_snan = __builtin_nansf("");
+volatile double d_snan = __builtin_nans("");
+volatile long double ld_snan = __builtin_nansl("");
+
+int issignaling_f(float x)
+{
+    union { float f; uint32_t u; } u = { .f = x };
+    return (u.u & 0x7fffffff) > 0x7f800000 && (u.u & 0x400000) == 0;
+}
+
+int issignaling_d(double x)
+{
+    union { double d; uint64_t u; } u = { .d = x };
+    return (((u.u & UINT64_C(0x7fffffffffffffff)) >
+            UINT64_C(0x7ff0000000000000)) &&
+            (u.u & UINT64_C(0x8000000000000)) == 0);
+}
+
+int issignaling_ld(long double x)
+{
+    union {
+        long double ld;
+        struct { uint64_t sig; uint16_t sign_exp; } s;
+    } u = { .ld = x };
+    return ((u.s.sign_exp & 0x7fff) == 0x7fff &&
+            (u.s.sig >> 63) != 0 &&
+            (u.s.sig & UINT64_C(0x4000000000000000)) == 0);
+}
+
+int main(void)
+{
+    int ret = 0;
+    ld_res = f_snan;
+    if (issignaling_ld(ld_res)) {
+        printf("FAIL: float -> long double\n");
+        ret = 1;
+    }
+    ld_res = d_snan;
+    if (issignaling_ld(ld_res)) {
+        printf("FAIL: double -> long double\n");
+        ret = 1;
+    }
+    f_res = ld_snan;
+    if (issignaling_d(f_res)) {
+        printf("FAIL: long double -> float\n");
+        ret = 1;
+    }
+    d_res = ld_snan;
+    if (issignaling_d(d_res)) {
+        printf("FAIL: long double -> double\n");
+        ret = 1;
+    }
+    return ret;
+}