Loading...
1/*
2 * Divide a 64-bit unsigned number by a 32-bit unsigned number.
3 * This routine assumes that the top 32 bits of the dividend are
4 * non-zero to start with.
5 * On entry, r3 points to the dividend, which get overwritten with
6 * the 64-bit quotient, and r4 contains the divisor.
7 * On exit, r3 contains the remainder.
8 *
9 * Copyright (C) 2002 Paul Mackerras, IBM Corp.
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 */
16#include "ppc_asm.h"
17
18 .globl __div64_32
19__div64_32:
20 lwz r5,0(r3) # get the dividend into r5/r6
21 lwz r6,4(r3)
22 cmplw r5,r4
23 li r7,0
24 li r8,0
25 blt 1f
26 divwu r7,r5,r4 # if dividend.hi >= divisor,
27 mullw r0,r7,r4 # quotient.hi = dividend.hi / divisor
28 subf. r5,r0,r5 # dividend.hi %= divisor
29 beq 3f
301: mr r11,r5 # here dividend.hi != 0
31 andis. r0,r5,0xc000
32 bne 2f
33 cntlzw r0,r5 # we are shifting the dividend right
34 li r10,-1 # to make it < 2^32, and shifting
35 srw r10,r10,r0 # the divisor right the same amount,
36 addc r9,r4,r10 # rounding up (so the estimate cannot
37 andc r11,r6,r10 # ever be too large, only too small)
38 andc r9,r9,r10
39 addze r9,r9
40 or r11,r5,r11
41 rotlw r9,r9,r0
42 rotlw r11,r11,r0
43 divwu r11,r11,r9 # then we divide the shifted quantities
442: mullw r10,r11,r4 # to get an estimate of the quotient,
45 mulhwu r9,r11,r4 # multiply the estimate by the divisor,
46 subfc r6,r10,r6 # take the product from the divisor,
47 add r8,r8,r11 # and add the estimate to the accumulated
48 subfe. r5,r9,r5 # quotient
49 bne 1b
503: cmplw r6,r4
51 blt 4f
52 divwu r0,r6,r4 # perform the remaining 32-bit division
53 mullw r10,r0,r4 # and get the remainder
54 add r8,r8,r0
55 subf r6,r10,r6
564: stw r7,0(r3) # return the quotient in *r3
57 stw r8,4(r3)
58 mr r3,r6 # return the remainder in r3
59 blr
60
61/*
62 * Extended precision shifts.
63 *
64 * Updated to be valid for shift counts from 0 to 63 inclusive.
65 * -- Gabriel
66 *
67 * R3/R4 has 64 bit value
68 * R5 has shift count
69 * result in R3/R4
70 *
71 * ashrdi3: arithmetic right shift (sign propagation)
72 * lshrdi3: logical right shift
73 * ashldi3: left shift
74 */
75 .globl __ashrdi3
76__ashrdi3:
77 subfic r6,r5,32
78 srw r4,r4,r5 # LSW = count > 31 ? 0 : LSW >> count
79 addi r7,r5,32 # could be xori, or addi with -32
80 slw r6,r3,r6 # t1 = count > 31 ? 0 : MSW << (32-count)
81 rlwinm r8,r7,0,32 # t3 = (count < 32) ? 32 : 0
82 sraw r7,r3,r7 # t2 = MSW >> (count-32)
83 or r4,r4,r6 # LSW |= t1
84 slw r7,r7,r8 # t2 = (count < 32) ? 0 : t2
85 sraw r3,r3,r5 # MSW = MSW >> count
86 or r4,r4,r7 # LSW |= t2
87 blr
88
89 .globl __ashldi3
90__ashldi3:
91 subfic r6,r5,32
92 slw r3,r3,r5 # MSW = count > 31 ? 0 : MSW << count
93 addi r7,r5,32 # could be xori, or addi with -32
94 srw r6,r4,r6 # t1 = count > 31 ? 0 : LSW >> (32-count)
95 slw r7,r4,r7 # t2 = count < 32 ? 0 : LSW << (count-32)
96 or r3,r3,r6 # MSW |= t1
97 slw r4,r4,r5 # LSW = LSW << count
98 or r3,r3,r7 # MSW |= t2
99 blr
100
101 .globl __lshrdi3
102__lshrdi3:
103 subfic r6,r5,32
104 srw r4,r4,r5 # LSW = count > 31 ? 0 : LSW >> count
105 addi r7,r5,32 # could be xori, or addi with -32
106 slw r6,r3,r6 # t1 = count > 31 ? 0 : MSW << (32-count)
107 srw r7,r3,r7 # t2 = count < 32 ? 0 : MSW >> (count-32)
108 or r4,r4,r6 # LSW |= t1
109 srw r3,r3,r5 # MSW = MSW >> count
110 or r4,r4,r7 # LSW |= t2
111 blr
1/*
2 * Divide a 64-bit unsigned number by a 32-bit unsigned number.
3 * This routine assumes that the top 32 bits of the dividend are
4 * non-zero to start with.
5 * On entry, r3 points to the dividend, which get overwritten with
6 * the 64-bit quotient, and r4 contains the divisor.
7 * On exit, r3 contains the remainder.
8 *
9 * Copyright (C) 2002 Paul Mackerras, IBM Corp.
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 */
16#include "ppc_asm.h"
17
18 .globl __div64_32
19__div64_32:
20 lwz r5,0(r3) # get the dividend into r5/r6
21 lwz r6,4(r3)
22 cmplw r5,r4
23 li r7,0
24 li r8,0
25 blt 1f
26 divwu r7,r5,r4 # if dividend.hi >= divisor,
27 mullw r0,r7,r4 # quotient.hi = dividend.hi / divisor
28 subf. r5,r0,r5 # dividend.hi %= divisor
29 beq 3f
301: mr r11,r5 # here dividend.hi != 0
31 andis. r0,r5,0xc000
32 bne 2f
33 cntlzw r0,r5 # we are shifting the dividend right
34 li r10,-1 # to make it < 2^32, and shifting
35 srw r10,r10,r0 # the divisor right the same amount,
36 addc r9,r4,r10 # rounding up (so the estimate cannot
37 andc r11,r6,r10 # ever be too large, only too small)
38 andc r9,r9,r10
39 addze r9,r9
40 or r11,r5,r11
41 rotlw r9,r9,r0
42 rotlw r11,r11,r0
43 divwu r11,r11,r9 # then we divide the shifted quantities
442: mullw r10,r11,r4 # to get an estimate of the quotient,
45 mulhwu r9,r11,r4 # multiply the estimate by the divisor,
46 subfc r6,r10,r6 # take the product from the divisor,
47 add r8,r8,r11 # and add the estimate to the accumulated
48 subfe. r5,r9,r5 # quotient
49 bne 1b
503: cmplw r6,r4
51 blt 4f
52 divwu r0,r6,r4 # perform the remaining 32-bit division
53 mullw r10,r0,r4 # and get the remainder
54 add r8,r8,r0
55 subf r6,r10,r6
564: stw r7,0(r3) # return the quotient in *r3
57 stw r8,4(r3)
58 mr r3,r6 # return the remainder in r3
59 blr
60
61/*
62 * Extended precision shifts.
63 *
64 * Updated to be valid for shift counts from 0 to 63 inclusive.
65 * -- Gabriel
66 *
67 * R3/R4 has 64 bit value
68 * R5 has shift count
69 * result in R3/R4
70 *
71 * ashrdi3: arithmetic right shift (sign propagation)
72 * lshrdi3: logical right shift
73 * ashldi3: left shift
74 */
75 .globl __ashrdi3
76__ashrdi3:
77 subfic r6,r5,32
78 srw r4,r4,r5 # LSW = count > 31 ? 0 : LSW >> count
79 addi r7,r5,32 # could be xori, or addi with -32
80 slw r6,r3,r6 # t1 = count > 31 ? 0 : MSW << (32-count)
81 rlwinm r8,r7,0,32 # t3 = (count < 32) ? 32 : 0
82 sraw r7,r3,r7 # t2 = MSW >> (count-32)
83 or r4,r4,r6 # LSW |= t1
84 slw r7,r7,r8 # t2 = (count < 32) ? 0 : t2
85 sraw r3,r3,r5 # MSW = MSW >> count
86 or r4,r4,r7 # LSW |= t2
87 blr
88
89 .globl __ashldi3
90__ashldi3:
91 subfic r6,r5,32
92 slw r3,r3,r5 # MSW = count > 31 ? 0 : MSW << count
93 addi r7,r5,32 # could be xori, or addi with -32
94 srw r6,r4,r6 # t1 = count > 31 ? 0 : LSW >> (32-count)
95 slw r7,r4,r7 # t2 = count < 32 ? 0 : LSW << (count-32)
96 or r3,r3,r6 # MSW |= t1
97 slw r4,r4,r5 # LSW = LSW << count
98 or r3,r3,r7 # MSW |= t2
99 blr
100
101 .globl __lshrdi3
102__lshrdi3:
103 subfic r6,r5,32
104 srw r4,r4,r5 # LSW = count > 31 ? 0 : LSW >> count
105 addi r7,r5,32 # could be xori, or addi with -32
106 slw r6,r3,r6 # t1 = count > 31 ? 0 : MSW << (32-count)
107 srw r7,r3,r7 # t2 = count < 32 ? 0 : MSW >> (count-32)
108 or r4,r4,r6 # LSW |= t1
109 srw r3,r3,r5 # MSW = MSW >> count
110 or r4,r4,r7 # LSW |= t2
111 blr