1//===----------------------Hexagon builtin routine ------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9 .macro FUNCTION_BEGIN name
10 .text
11 .p2align 5
12 .globl \name
13 .type \name, @function
14\name:
15 .endm
16
17 .macro FUNCTION_END name
18 .size \name, . - \name
19 .endm
20
21
22FUNCTION_BEGIN __hexagon_moddi3
23 {
24 p3 = tstbit(r1,#31)
25 }
26 {
27 r1:0 = abs(r1:0)
28 r3:2 = abs(r3:2)
29 }
30 {
31 r6 = cl0(r1:0) // count leading 0's of dividend (numerator)
32 r7 = cl0(r3:2) // count leading 0's of divisor (denominator)
33 r5:4 = r3:2 // divisor moved into working registers
34 r3:2 = r1:0 // dividend is the initial remainder, r3:2 contains remainder
35 }
36 {
37 r10 = sub(r7,r6) // left shift count for bit & divisor
38 r1:0 = #0 // initialize quotient to 0
39 r15:14 = #1 // initialize bit to 1
40 }
41 {
42 r11 = add(r10,#1) // loop count is 1 more than shift count
43 r13:12 = lsl(r5:4,r10) // shift divisor msb into same bit position as dividend msb
44 r15:14 = lsl(r15:14,r10) // shift the bit left by same amount as divisor
45 }
46 {
47 p0 = cmp.gtu(r5:4,r3:2) // check if divisor > dividend
48 loop0(1f,r11) // register loop
49 }
50 {
51 if (p0) jump .hexagon_moddi3_return // if divisor > dividend, we're done, so return
52 }
53 .falign
541:
55 {
56 p0 = cmp.gtu(r13:12,r3:2) // set predicate reg if shifted divisor > current remainder
57 }
58 {
59 r7:6 = sub(r3:2, r13:12) // subtract shifted divisor from current remainder
60 r9:8 = add(r1:0, r15:14) // save current quotient to temp (r9:8)
61 }
62 {
63 r1:0 = vmux(p0, r1:0, r9:8) // choose either current quotient or new quotient (r9:8)
64 r3:2 = vmux(p0, r3:2, r7:6) // choose either current remainder or new remainder (r7:6)
65 }
66 {
67 r15:14 = lsr(r15:14, #1) // shift bit right by 1 for next iteration
68 r13:12 = lsr(r13:12, #1) // shift "shifted divisor" right by 1 for next iteration
69 }:endloop0
70
71.hexagon_moddi3_return:
72 {
73 r1:0 = neg(r3:2)
74 }
75 {
76 r1:0 = vmux(p3,r1:0,r3:2)
77 jumpr r31
78 }
79FUNCTION_END __hexagon_moddi3
80
81 .globl __qdsp_moddi3
82 .set __qdsp_moddi3, __hexagon_moddi3
83

source code of compiler-rt/lib/builtins/hexagon/moddi3.S