remove special nan handling from x86 sqrt asm

a double precision nan, when converted to extended (80-bit) precision,
will never end in 0x400, since the corresponding bits do not exist in
the original double precision value. thus there's no need to waste
time and code size on this check.

diff --git a/src/math/i386/sqrt.s b/src/math/i386/sqrt.s
index 1bd3b05..8289d09 100644 (file)
--- a/src/math/i386/sqrt.s
+++ b/src/math/i386/sqrt.s
@@ -10,9 +10,6 @@ sqrt: fldl 4(%esp)
        and $0x7ff,%ecx
        cmp $0x400,%ecx
        jnz 1f
        and $0x7ff,%ecx
        cmp $0x400,%ecx
        jnz 1f

-       mov 8(%esp),%cx
-       inc %cx
-       jo 1f

        and $0x200,%eax
        sub $0x100,%eax
        sub %eax,(%esp)
        and $0x200,%eax
        sub $0x100,%eax
        sub %eax,(%esp)