math: x86_64 version of expl, fixed some comments in the i386 version

[musl] / src / math / i386 / expl.s

diff --git a/src/math/i386/expl.s b/src/math/i386/expl.s
index 3f2f707..8ceb40d 100644 (file)
--- a/src/math/i386/expl.s
+++ b/src/math/i386/expl.s
@@ -1,6 +1,7 @@
 # exp(x) = 2^hi + 2^hi (2^lo - 1)
 # where hi+lo = log2e*x with 128bit precision
 # exact log2e*x calculation depends on nearest rounding mode
+# using the exact multiplication method of Dekker and Veltkamp
 
 .global expl
 .type expl,@function
@@ -35,7 +36,6 @@ expl:
                # should be 0x1.71547652b82fe178p0 == 0x3fff b8aa3b29 5c17f0bc
                # it will be wrong on non-nearest rounding mode
 3:     fldl2e
-#      subl $32, %esp
        subl $44, %esp
                # hi = log2e_hi*x
                # 2^hi = exp2l(hi)
@@ -54,7 +54,7 @@ expl:
        fldt 16(%esp)
                # fpu stack: 2^hi x hi
                # exact mult: x*log2e
-       fld %st(1) # x
+       fld %st(1)
                # c = 0x1p32+1
        pushl $0x41f00000
        pushl $0x00100000