xref: /minix3/sys/external/bsd/compiler_rt/dist/lib/builtins/lshrdi3.c (revision 0a6a1f1d05b60e214de2f05a7310ddd1f0e590e7)
1*0a6a1f1dSLionel Sambuc /* ===-- lshrdi3.c - Implement __lshrdi3 -----------------------------------===
2*0a6a1f1dSLionel Sambuc  *
3*0a6a1f1dSLionel Sambuc  *                     The LLVM Compiler Infrastructure
4*0a6a1f1dSLionel Sambuc  *
5*0a6a1f1dSLionel Sambuc  * This file is dual licensed under the MIT and the University of Illinois Open
6*0a6a1f1dSLionel Sambuc  * Source Licenses. See LICENSE.TXT for details.
7*0a6a1f1dSLionel Sambuc  *
8*0a6a1f1dSLionel Sambuc  * ===----------------------------------------------------------------------===
9*0a6a1f1dSLionel Sambuc  *
10*0a6a1f1dSLionel Sambuc  * This file implements __lshrdi3 for the compiler_rt library.
11*0a6a1f1dSLionel Sambuc  *
12*0a6a1f1dSLionel Sambuc  * ===----------------------------------------------------------------------===
13*0a6a1f1dSLionel Sambuc  */
14*0a6a1f1dSLionel Sambuc 
15*0a6a1f1dSLionel Sambuc #include "int_lib.h"
16*0a6a1f1dSLionel Sambuc 
17*0a6a1f1dSLionel Sambuc /* Returns: logical a >> b */
18*0a6a1f1dSLionel Sambuc 
19*0a6a1f1dSLionel Sambuc /* Precondition:  0 <= b < bits_in_dword */
20*0a6a1f1dSLionel Sambuc 
ARM_EABI_FNALIAS(llsr,lshrdi3)21*0a6a1f1dSLionel Sambuc ARM_EABI_FNALIAS(llsr, lshrdi3)
22*0a6a1f1dSLionel Sambuc 
23*0a6a1f1dSLionel Sambuc COMPILER_RT_ABI di_int
24*0a6a1f1dSLionel Sambuc __lshrdi3(di_int a, si_int b)
25*0a6a1f1dSLionel Sambuc {
26*0a6a1f1dSLionel Sambuc     const int bits_in_word = (int)(sizeof(si_int) * CHAR_BIT);
27*0a6a1f1dSLionel Sambuc     udwords input;
28*0a6a1f1dSLionel Sambuc     udwords result;
29*0a6a1f1dSLionel Sambuc     input.all = a;
30*0a6a1f1dSLionel Sambuc     if (b & bits_in_word)  /* bits_in_word <= b < bits_in_dword */
31*0a6a1f1dSLionel Sambuc     {
32*0a6a1f1dSLionel Sambuc         result.s.high = 0;
33*0a6a1f1dSLionel Sambuc         result.s.low = input.s.high >> (b - bits_in_word);
34*0a6a1f1dSLionel Sambuc     }
35*0a6a1f1dSLionel Sambuc     else  /* 0 <= b < bits_in_word */
36*0a6a1f1dSLionel Sambuc     {
37*0a6a1f1dSLionel Sambuc         if (b == 0)
38*0a6a1f1dSLionel Sambuc             return a;
39*0a6a1f1dSLionel Sambuc         result.s.high  = input.s.high >> b;
40*0a6a1f1dSLionel Sambuc         result.s.low = (input.s.high << (bits_in_word - b)) | (input.s.low >> b);
41*0a6a1f1dSLionel Sambuc     }
42*0a6a1f1dSLionel Sambuc     return result.all;
43*0a6a1f1dSLionel Sambuc }
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