softfloat: For Mips only, correct default NaN values

Only for Mips platform, and only for cases when snan_bit_is_one is 0,
correct default NaN values (in their 16-, 32-, and 64-bit flavors).

For more info, see [1], page 84, Table 6.3 "Value Supplied When a New
Quiet NaN Is Created", and [2], page 52, Table 3.7 "Default NaN
Encodings".

[1] "MIPS Architecture For Programmers Volume II-A:
    The MIPS64 Instruction Set Reference Manual",
    Imagination Technologies LTD, Revision 6.04, November 13, 2015

[2] "MIPS Architecture for Programmers Volume IV-j:
    The MIPS32 SIMD Architecture Module",
    Imagination Technologies LTD, Revision 1.12, February 3, 2016

Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>

diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h
index 981d66573ec7a2929d87094262a50fb2b98b6d3d..a1bcb46a47793af0c67c5ddd489ea4ab7d6efe54 100644 (file)
--- a/fpu/softfloat-specialize.h
+++ b/fpu/softfloat-specialize.h
@@ -97,7 +97,11 @@ float16 float16_default_nan(float_status *status)
     if (status->snan_bit_is_one) {
         return const_float16(0x7DFF);
     } else {
+#if defined(TARGET_MIPS)
+        return const_float16(0x7E00);
+#else
         return const_float16(0xFE00);
+#endif
     }
 #endif
 }
@@ -116,7 +120,11 @@ float32 float32_default_nan(float_status *status)
     if (status->snan_bit_is_one) {
         return const_float32(0x7FBFFFFF);
     } else {
+#if defined(TARGET_MIPS)
+        return const_float32(0x7FC00000);
+#else
         return const_float32(0xFFC00000);
+#endif
     }
 #endif
 }
@@ -135,7 +143,11 @@ float64 float64_default_nan(float_status *status)
     if (status->snan_bit_is_one) {
         return const_float64(LIT64(0x7FF7FFFFFFFFFFFF));
     } else {
+#if defined(TARGET_MIPS)
+        return const_float64(LIT64(0x7FF8000000000000));
+#else
         return const_float64(LIT64(0xFFF8000000000000));
+#endif
     }
 #endif
 }