compiler-rt/lib/builtins/i386/floatdidf.S

   1 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   2 // See https://llvm.org/LICENSE.txt for license information.
   3 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   4
   5 #include "../assembly.h"
   6
   7 // double __floatdidf(du_int a);
   8
   9 #ifdef __i386__
  10
  11 CONST_SECTION
  12
  13         .balign 16
  14 twop52:
  15         .quad 0x4330000000000000
  16
  17         .balign 16
  18 twop32:
  19         .quad 0x41f0000000000000
  20
  21 #define REL_ADDR(_a)    (_a)-0b(%eax)
  22
  23 .text
  24 .balign 4
  25 DEFINE_COMPILERRT_FUNCTION(__floatdidf)
  26         cvtsi2sd        8(%esp),                        %xmm1
  27         movss           4(%esp),                        %xmm0 // low 32 bits of a
  28         calll           0f
  29 0:      popl            %eax
  30         mulsd           REL_ADDR(twop32),       %xmm1 // a_hi as a double (without rounding)
  31         movsd           REL_ADDR(twop52),       %xmm2 // 0x1.0p52
  32         subsd           %xmm2,                          %xmm1 // a_hi - 0x1p52 (no rounding occurs)
  33         orpd            %xmm2,                          %xmm0 // 0x1p52 + a_lo (no rounding occurs)
  34         addsd           %xmm1,                          %xmm0 // a_hi + a_lo   (round happens here)
  35         movsd           %xmm0,                     4(%esp)
  36         fldl       4(%esp)
  37         ret
  38 END_COMPILERRT_FUNCTION(__floatdidf)
  39
  40 #endif // __i386__
  41
  42 NO_EXEC_STACK_DIRECTIVE
  43