1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "asm_support_arm.S"
18
19.section .text
20// This function is used to check for the CPU's support for the sdiv
21// instruction at runtime.  It will either return the value 1 or
22// will cause an invalid instruction trap (SIGILL signal).  The
23// caller must arrange for the signal handler to set the r0
24// register to 0 and move the pc forward by 4 bytes (to skip
25// the invalid instruction).
26ENTRY artCheckForArmSdivInstruction
27  mov r1,#1
28  // depending on the architecture, the assembler will not allow an
29  // sdiv instruction, so we will have to output the bytes directly.
30
31  // sdiv r0,r1,r1 is two words: 0xfb91 0xf1f0.  We need little endian.
32  .byte 0x91,0xfb,0xf1,0xf0
33
34  // if the divide worked, r0 will have the value #1 (result of sdiv).
35  // It will have 0 otherwise (set by the signal handler)
36  // the value is just returned from this function.
37  bx lr
38END artCheckForArmSdivInstruction
39