1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <linux/linkage.h>
3
4 /*
5 * modulo operation for 32 bit integers.
6 * Input : op1 in Reg r5
7 * op2 in Reg r6
8 * Output: op1 mod op2 in Reg r3
9 */
10
11 .text
12 .globl __modsi3
13 .type __modsi3, @function
14 .ent __modsi3
15
16 __modsi3:
17 .frame r1, 0, r15
18
19 addik r1, r1, -16
20 swi r28, r1, 0
21 swi r29, r1, 4
22 swi r30, r1, 8
23 swi r31, r1, 12
24
25 beqi r6, div_by_zero /* div_by_zero
26 beqi r5, result_is_zero /* result i
27 bgeid r5, r5_pos
28 /* get the sign of the result [ depend
29 add r28, r5, r0
30 rsubi r5, r5, 0 /* make r5 po
31 r5_pos:
32 bgei r6, r6_pos
33 rsubi r6, r6, 0 /* make r6 po
34 r6_pos:
35 addik r3, r0, 0 /* clear mod */
36 addik r30, r0, 0 /* clear div */
37 addik r29, r0, 32 /* initialize the
38 /* first part try to find the first '1' in the
39 div1:
40 add r5, r5, r5 /* left shift logic
41 bgeid r5, div1
42 addik r29, r29, -1
43 div2:
44 /* left shift logical r5 get the '1' i
45 add r5, r5, r5
46 addc r3, r3, r3 /* move that bit in
47 rsub r31, r6, r3 /* try to subtract
48 blti r31, mod_too_small
49 /* move the r31 to mod since the resul
50 or r3, r0, r31
51 addik r30, r30, 1
52 mod_too_small:
53 addik r29, r29, -1
54 beqi r29, loop_end
55 add r30, r30, r30 /* shift in the
56 bri div2 /* div2 */
57 loop_end:
58 bgei r28, return_here
59 brid return_here
60 rsubi r3, r3, 0 /* negate the result
61 div_by_zero:
62 result_is_zero:
63 or r3, r0, r0 /* set result to 0
64 return_here:
65 /* restore values of csrs and that of r3 and t
66 lwi r28, r1, 0
67 lwi r29, r1, 4
68 lwi r30, r1, 8
69 lwi r31, r1, 12
70 rtsd r15, 8
71 addik r1, r1, 16
72
73 .size __modsi3, . - __modsi3
74 .end __modsi3
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