arm_sdiv.S revision 235e77bd9f19e4faefda109be40f8744f3a66f40 
1// This function is used to check for the CPU's support for the sdiv
2// instruction at runtime.  It will either return the value 1 or
3// will cause an invalid instruction trap (SIGILL signal).  The
4// caller must arrange for the signal handler to set the r0
5// register to 0 and move the pc forward by 4 bytes (to skip
6// the invalid instruction).
7
8
9#include "asm_support_arm.S"
10
11.section .text
12ENTRY_NO_HIDE CheckForARMSDIVInstruction
13  mov r1,#1
14  // depending on the architecture, the assembler will not allow an
15  // sdiv instruction, so we will have to output the bytes directly.
16
17  // sdiv r0,r1,r1 is two words: 0xfb91 0xf1f0.  We need little endian.
18  .byte 0x91,0xfb,0xf1,0xf0
19
20  // if the divide worked, r0 will have the value #1 (result of sdiv).
21  // It will have 0 otherwise (set by the signal handler)
22  // the value is just returned from this function.
23  bx lr
24  END CheckForARMSDIVInstruction
25