xref: /openbmc/qemu/target/s390x/tcg/int_helper.c (revision 2df1eb27)
1 /*
2  *  S/390 integer helper routines
3  *
4  *  Copyright (c) 2009 Ulrich Hecht
5  *  Copyright (c) 2009 Alexander Graf
6  *
7  * This library is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * This library is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include "qemu/osdep.h"
22 #include "cpu.h"
23 #include "s390x-internal.h"
24 #include "tcg_s390x.h"
25 #include "exec/exec-all.h"
26 #include "qemu/host-utils.h"
27 #include "exec/helper-proto.h"
28 #include "exec/cpu_ldst.h"
29 
30 /* #define DEBUG_HELPER */
31 #ifdef DEBUG_HELPER
32 #define HELPER_LOG(x...) qemu_log(x)
33 #else
34 #define HELPER_LOG(x...)
35 #endif
36 
37 /* 64/32 -> 32 signed division */
38 uint64_t HELPER(divs32)(CPUS390XState *env, int64_t a, int64_t b64)
39 {
40     int32_t b = b64;
41     int64_t q, r;
42 
43     if (b == 0) {
44         tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
45     }
46 
47     q = a / b;
48     r = a % b;
49 
50     /* Catch non-representable quotient.  */
51     if (q != (int32_t)q) {
52         tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
53     }
54 
55     return deposit64(q, 32, 32, r);
56 }
57 
58 /* 64/32 -> 32 unsigned division */
59 uint64_t HELPER(divu32)(CPUS390XState *env, uint64_t a, uint64_t b64)
60 {
61     uint32_t b = b64;
62     uint64_t q, r;
63 
64     if (b == 0) {
65         tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
66     }
67 
68     q = a / b;
69     r = a % b;
70 
71     /* Catch non-representable quotient.  */
72     if (q != (uint32_t)q) {
73         tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
74     }
75 
76     return deposit64(q, 32, 32, r);
77 }
78 
79 /* 64/64 -> 64 signed division */
80 Int128 HELPER(divs64)(CPUS390XState *env, int64_t a, int64_t b)
81 {
82     /* Catch divide by zero, and non-representable quotient (MIN / -1).  */
83     if (b == 0 || (b == -1 && a == (1ll << 63))) {
84         tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
85     }
86     return int128_make128(a / b, a % b);
87 }
88 
89 /* 128 -> 64/64 unsigned division */
90 Int128 HELPER(divu64)(CPUS390XState *env, uint64_t ah, uint64_t al, uint64_t b)
91 {
92     if (b != 0) {
93         uint64_t r = divu128(&al, &ah, b);
94         if (ah == 0) {
95             return int128_make128(al, r);
96         }
97     }
98     /* divide by zero or overflow */
99     tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
100 }
101 
102 void HELPER(cvb)(CPUS390XState *env, uint32_t r1, uint64_t dec)
103 {
104     int64_t pow10 = 1, bin = 0;
105     int digit, sign;
106 
107     sign = dec & 0xf;
108     if (sign < 0xa) {
109         tcg_s390_data_exception(env, 0, GETPC());
110     }
111     dec >>= 4;
112 
113     while (dec) {
114         digit = dec & 0xf;
115         if (digit > 0x9) {
116             tcg_s390_data_exception(env, 0, GETPC());
117         }
118         dec >>= 4;
119         bin += digit * pow10;
120         pow10 *= 10;
121     }
122 
123     if (sign == 0xb || sign == 0xd) {
124         bin = -bin;
125     }
126 
127     /* R1 is updated even on fixed-point-divide exception. */
128     env->regs[r1] = (env->regs[r1] & 0xffffffff00000000ULL) | (uint32_t)bin;
129     if (bin != (int32_t)bin) {
130         tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
131     }
132 }
133 
134 uint64_t HELPER(cvbg)(CPUS390XState *env, Int128 dec)
135 {
136     uint64_t dec64[] = {int128_getlo(dec), int128_gethi(dec)};
137     int64_t bin = 0, pow10, tmp;
138     int digit, i, sign;
139 
140     sign = dec64[0] & 0xf;
141     if (sign < 0xa) {
142         tcg_s390_data_exception(env, 0, GETPC());
143     }
144     dec64[0] >>= 4;
145     pow10 = (sign == 0xb || sign == 0xd) ? -1 : 1;
146 
147     for (i = 1; i < 20; i++) {
148         digit = dec64[i >> 4] & 0xf;
149         if (digit > 0x9) {
150             tcg_s390_data_exception(env, 0, GETPC());
151         }
152         dec64[i >> 4] >>= 4;
153         /*
154          * Prepend the next digit and check for overflow. The multiplication
155          * cannot overflow, since, conveniently, the int64_t limits are
156          * approximately +-9.2E+18. If bin is zero, the addition cannot
157          * overflow. Otherwise bin is known to have the same sign as the rhs
158          * addend, in which case overflow happens if and only if the result
159          * has a different sign.
160          */
161         tmp = bin + pow10 * digit;
162         if (bin && ((tmp ^ bin) < 0)) {
163             tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
164         }
165         bin = tmp;
166         pow10 *= 10;
167     }
168 
169     g_assert(!dec64[0]);
170     if (dec64[1]) {
171         tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
172     }
173 
174     return bin;
175 }
176 
177 uint64_t HELPER(cvd)(int32_t reg)
178 {
179     /* positive 0 */
180     uint64_t dec = 0x0c;
181     int64_t bin = reg;
182     int shift;
183 
184     if (bin < 0) {
185         bin = -bin;
186         dec = 0x0d;
187     }
188 
189     for (shift = 4; (shift < 64) && bin; shift += 4) {
190         dec |= (bin % 10) << shift;
191         bin /= 10;
192     }
193 
194     return dec;
195 }
196 
197 Int128 HELPER(cvdg)(int64_t reg)
198 {
199     /* positive 0 */
200     Int128 dec = int128_make64(0x0c);
201     Int128 bin = int128_makes64(reg);
202     Int128 base = int128_make64(10);
203     int shift;
204 
205     if (!int128_nonneg(bin)) {
206         bin = int128_neg(bin);
207         dec = int128_make64(0x0d);
208     }
209 
210     for (shift = 4; (shift < 128) && int128_nz(bin); shift += 4) {
211         dec = int128_or(dec, int128_lshift(int128_remu(bin, base), shift));
212         bin = int128_divu(bin, base);
213     }
214 
215     return dec;
216 }
217 
218 uint64_t HELPER(popcnt)(uint64_t val)
219 {
220     /* Note that we don't fold past bytes. */
221     val = (val & 0x5555555555555555ULL) + ((val >> 1) & 0x5555555555555555ULL);
222     val = (val & 0x3333333333333333ULL) + ((val >> 2) & 0x3333333333333333ULL);
223     val = (val + (val >> 4)) & 0x0f0f0f0f0f0f0f0fULL;
224     return val;
225 }
226