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dff8da6b | 1 | /* Copyright (C) 1996-2024 Free Software Foundation, Inc. |
60c74cf0 UD |
2 | This file is part of the GNU C Library. |
3 | ||
4 | The GNU C Library is free software; you can redistribute it and/or | |
3214b89b AJ |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
60c74cf0 UD |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
3214b89b | 12 | Lesser General Public License for more details. |
60c74cf0 | 13 | |
3214b89b | 14 | You should have received a copy of the GNU Lesser General Public |
ab84e3ff | 15 | License along with the GNU C Library. If not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
60c74cf0 | 17 | |
bd68d850 | 18 | #include "div_libc.h" |
60c74cf0 | 19 | |
bd68d850 RH |
20 | #undef FRAME |
21 | #ifdef __alpha_fix__ | |
22 | #define FRAME 0 | |
60c74cf0 | 23 | #else |
bd68d850 | 24 | #define FRAME 16 |
60c74cf0 UD |
25 | #endif |
26 | ||
bd68d850 RH |
27 | #undef X |
28 | #undef Y | |
29 | #define X $17 | |
30 | #define Y $18 | |
31 | ||
60c74cf0 UD |
32 | .set noat |
33 | ||
34 | .align 4 | |
35 | .globl ldiv | |
36 | .ent ldiv | |
37 | ldiv: | |
bd68d850 RH |
38 | .frame sp, FRAME, ra |
39 | #if FRAME > 0 | |
40 | lda sp, -FRAME(sp) | |
41 | #endif | |
60c74cf0 | 42 | #ifdef PROF |
bd68d850 | 43 | .set macro |
60c74cf0 UD |
44 | ldgp gp, 0(pv) |
45 | lda AT, _mcount | |
46 | jsr AT, (AT), _mcount | |
bd68d850 | 47 | .set nomacro |
60c74cf0 UD |
48 | .prologue 1 |
49 | #else | |
50 | .prologue 0 | |
51 | #endif | |
52 | ||
bd68d850 | 53 | beq Y, $divbyzero |
a61c91b0 RH |
54 | excb |
55 | mf_fpcr $f10 | |
bd68d850 RH |
56 | |
57 | _ITOFT2 X, $f0, 0, Y, $f1, 8 | |
58 | ||
59 | .align 4 | |
60 | cvtqt $f0, $f0 | |
61 | cvtqt $f1, $f1 | |
62 | divt/c $f0, $f1, $f0 | |
63 | unop | |
64 | ||
65 | /* Check to see if X fit in the double as an exact value. */ | |
66 | sll X, (64-53), AT | |
67 | sra AT, (64-53), AT | |
68 | cmpeq X, AT, AT | |
69 | beq AT, $x_big | |
70 | ||
71 | /* If we get here, we're expecting exact results from the division. | |
72 | Do nothing else besides convert and clean up. */ | |
73 | cvttq/c $f0, $f0 | |
a61c91b0 RH |
74 | excb |
75 | mt_fpcr $f10 | |
bd68d850 RH |
76 | _FTOIT $f0, $0, 0 |
77 | ||
78 | $egress: | |
79 | mulq $0, Y, $1 | |
80 | subq X, $1, $1 | |
81 | ||
82 | stq $0, 0($16) | |
83 | stq $1, 8($16) | |
84 | mov $16, $0 | |
85 | ||
86 | #if FRAME > 0 | |
87 | lda sp, FRAME(sp) | |
88 | #endif | |
89 | ret | |
90 | ||
91 | .align 4 | |
92 | $x_big: | |
93 | /* If we get here, X is large enough that we don't expect exact | |
94 | results, and neither X nor Y got mis-translated for the fp | |
95 | division. Our task is to take the fp result, figure out how | |
96 | far it's off from the correct result and compute a fixup. */ | |
97 | ||
98 | #define Q v0 /* quotient */ | |
99 | #define R t0 /* remainder */ | |
100 | #define SY t1 /* scaled Y */ | |
101 | #define S t2 /* scalar */ | |
102 | #define QY t3 /* Q*Y */ | |
103 | ||
104 | /* The fixup code below can only handle unsigned values. */ | |
105 | or X, Y, AT | |
106 | mov $31, t5 | |
107 | blt AT, $fix_sign_in | |
108 | $fix_sign_in_ret1: | |
109 | cvttq/c $f0, $f0 | |
110 | ||
111 | _FTOIT $f0, Q, 8 | |
bd68d850 RH |
112 | $fix_sign_in_ret2: |
113 | mulq Q, Y, QY | |
a61c91b0 RH |
114 | excb |
115 | mt_fpcr $f10 | |
bd68d850 RH |
116 | |
117 | .align 4 | |
118 | subq QY, X, R | |
119 | mov Y, SY | |
120 | mov 1, S | |
121 | bgt R, $q_high | |
122 | ||
123 | $q_high_ret: | |
124 | subq X, QY, R | |
125 | mov Y, SY | |
126 | mov 1, S | |
127 | bgt R, $q_low | |
128 | ||
129 | $q_low_ret: | |
130 | negq Q, t4 | |
131 | cmovlbs t5, t4, Q | |
132 | br $egress | |
133 | ||
134 | .align 4 | |
135 | /* The quotient that we computed was too large. We need to reduce | |
136 | it by S such that Y*S >= R. Obviously the closer we get to the | |
137 | correct value the better, but overshooting high is ok, as we'll | |
138 | fix that up later. */ | |
139 | 0: | |
140 | addq SY, SY, SY | |
141 | addq S, S, S | |
142 | $q_high: | |
143 | cmpult SY, R, AT | |
144 | bne AT, 0b | |
145 | ||
146 | subq Q, S, Q | |
147 | unop | |
148 | subq QY, SY, QY | |
149 | br $q_high_ret | |
150 | ||
151 | .align 4 | |
5556231d | 152 | /* The quotient that we computed was too small. Divide Y by the |
bd68d850 RH |
153 | current remainder (R) and add that to the existing quotient (Q). |
154 | The expectation, of course, is that R is much smaller than X. */ | |
155 | /* Begin with a shift-up loop. Compute S such that Y*S >= R. We | |
156 | already have a copy of Y in SY and the value 1 in S. */ | |
157 | 0: | |
158 | addq SY, SY, SY | |
159 | addq S, S, S | |
160 | $q_low: | |
161 | cmpult SY, R, AT | |
162 | bne AT, 0b | |
163 | ||
164 | /* Shift-down and subtract loop. Each iteration compares our scaled | |
165 | Y (SY) with the remainder (R); if SY <= R then X is divisible by | |
166 | Y's scalar (S) so add it to the quotient (Q). */ | |
167 | 2: addq Q, S, t3 | |
168 | srl S, 1, S | |
169 | cmpule SY, R, AT | |
170 | subq R, SY, t4 | |
171 | ||
172 | cmovne AT, t3, Q | |
173 | cmovne AT, t4, R | |
174 | srl SY, 1, SY | |
175 | bne S, 2b | |
176 | ||
177 | br $q_low_ret | |
178 | ||
179 | .align 4 | |
180 | $fix_sign_in: | |
181 | /* If we got here, then X|Y is negative. Need to adjust everything | |
182 | such that we're doing unsigned division in the fixup loop. */ | |
183 | /* T5 is true if result should be negative. */ | |
184 | xor X, Y, AT | |
185 | cmplt AT, 0, t5 | |
186 | cmplt X, 0, AT | |
187 | negq X, t0 | |
188 | ||
189 | cmovne AT, t0, X | |
190 | cmplt Y, 0, AT | |
191 | negq Y, t0 | |
192 | ||
193 | cmovne AT, t0, Y | |
194 | blbc t5, $fix_sign_in_ret1 | |
195 | ||
196 | cvttq/c $f0, $f0 | |
197 | _FTOIT $f0, Q, 8 | |
198 | .align 3 | |
199 | negq Q, Q | |
200 | br $fix_sign_in_ret2 | |
60c74cf0 UD |
201 | |
202 | $divbyzero: | |
203 | mov a0, v0 | |
204 | lda a0, GEN_INTDIV | |
205 | call_pal PAL_gentrap | |
60c74cf0 UD |
206 | stq zero, 0(v0) |
207 | stq zero, 8(v0) | |
60c74cf0 | 208 | |
bd68d850 RH |
209 | #if FRAME > 0 |
210 | lda sp, FRAME(sp) | |
211 | #endif | |
212 | ret | |
60c74cf0 | 213 | |
bd68d850 | 214 | .end ldiv |
228f398a RH |
215 | |
216 | weak_alias (ldiv, lldiv) | |
dc0c31fb | 217 | weak_alias (ldiv, imaxdiv) |