1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <linux/linkage.h>
3
4 /*
5 * Divide operation for 32 bit integers.
6 * Input : Dividend in Reg r5
7 * Divisor in Reg r6
8 * Output: Result in Reg r3
9 */
10 .text
11 .globl __divsi3
12 .type __divsi3, @function
13 .ent __divsi3
14 __divsi3:
15 .frame r1, 0, r15
16
17 addik r1, r1, -16
18 swi r28, r1, 0
19 swi r29, r1, 4
20 swi r30, r1, 8
21 swi r31, r1, 12
22
23 beqi r6, div_by_zero /* div_by_zero
24 beqi r5, result_is_zero /* result i
25 bgeid r5, r5_pos
26 xor r28, r5, r6 /* get the sign of
27 rsubi r5, r5, 0 /* make r5 positive
28 r5_pos:
29 bgei r6, r6_pos
30 rsubi r6, r6, 0 /* make r6 positive
31 r6_pos:
32 addik r30, r0, 0 /* clear mod */
33 addik r3, r0, 0 /* clear div */
34 addik r29, r0, 32 /* initialize the
35
36 /* first part try to find the first '1
37 div0:
38 blti r5, div2 /* this traps r5 == 0
39 div1:
40 add r5, r5, r5 /* left shift logic
41 bgtid 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 r30, r30, r30 /* move that bit
47 rsub r31, r6, r30 /* try to subtrac
48 blti r31, mod_too_small
49 /* move the r31 to mod since the resul
50 or r30, r0, r31
51 addik r3, r3, 1
52 mod_too_small:
53 addik r29, r29, -1
54 beqi r29, loop_end
55 add r3, r3, r3 /* shift in the '1'
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 __divsi3, . - __divsi3
74 .end __divsi3
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