fix regression in x86_64 math asm with old binutils

the implicit-operand form of fucomip is rejected by binutils 2.19 and
perhaps other versions still in use. writing both operands explicitly
fixes the issue. there is no change to the resulting output.

commit a732e80d33b4fd6f510f7cec4f5573ef5d89bc4e was the source of this
regression.

diff --git a/src/math/x32/exp2l.s b/src/math/x32/exp2l.s
index dfb2bc7..e9edb96 100644 (file)
--- a/src/math/x32/exp2l.s
+++ b/src/math/x32/exp2l.s
@@ -6,7 +6,7 @@ expm1l:
        fmulp
        movl $0xc2820000,-4(%esp)
        flds -4(%esp)
-       fucomip %st(1)
+       fucomip %st(1),%st
        fld1
        jb 1f
                # x*log2e <= -65, return -1 without underflow
@@ -15,7 +15,7 @@ expm1l:
        ret
 1:     fld %st(1)
        fabs
-       fucomip %st(1)
+       fucomip %st(1),%st
        fstp %st(0)
        ja 1f
        f2xm1
@@ -48,7 +48,7 @@ exp2l:
        fld %st(1)
        fsub %st(1)
        faddp
-       fucomip %st(1)
+       fucomip %st(1),%st
        je 2f             # x - 0x1p63 + 0x1p63 == x
        movl $1,(%esp)
        flds (%esp)       # 0x1p-149

diff --git a/src/math/x86_64/exp2l.s b/src/math/x86_64/exp2l.s
index 0e9bdf9..effab2b 100644 (file)
--- a/src/math/x86_64/exp2l.s
+++ b/src/math/x86_64/exp2l.s
@@ -6,7 +6,7 @@ expm1l:
        fmulp
        movl $0xc2820000,-4(%rsp)
        flds -4(%rsp)
-       fucomip %st(1)
+       fucomip %st(1),%st
        fld1
        jb 1f
                # x*log2e <= -65, return -1 without underflow
@@ -15,7 +15,7 @@ expm1l:
        ret
 1:     fld %st(1)
        fabs
-       fucomip %st(1)
+       fucomip %st(1),%st
        fstp %st(0)
        ja 1f
        f2xm1
@@ -48,7 +48,7 @@ exp2l:
        fld %st(1)
        fsub %st(1)
        faddp
-       fucomip %st(1)
+       fucomip %st(1),%st
        je 2f             # x - 0x1p63 + 0x1p63 == x
        movl $1,(%rsp)
        flds (%rsp)       # 0x1p-149