xref: /freebsd/contrib/llvm-project/compiler-rt/lib/builtins/hexagon/moddi3.S (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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