@samitouri / QOSamiQemu
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1 /*
2 * Test DIEBR and DIDBR instructions.
3 *
4 * Most inputs were discovered by fuzzing and exercise various corner cases in
5 * the helpers.
6 *
7 * SPDX-License-Identifier: GPL-2.0-or-later
8 */
9 #include <signal.h>
10 #include <stdio.h>
11 #include <stdlib.h>
12 #include <asm/ucontext.h>
13
14 static void sigfpe_handler(int sig, siginfo_t *info, void *puc)
15 {
16 struct ucontext *uc = puc;
17 unsigned short *xr_insn;
18 int r;
19
20 xr_insn = (unsigned short *)(uc->uc_mcontext.regs.psw.addr - 6);
21 r = *xr_insn & 0xf;
22 uc->uc_mcontext.regs.gprs[r] = sig;
23 }
24
25 #define DIVIDE_TO_INTEGER(name, floatN) \
26 static inline __attribute__((__always_inline__)) int \
27 name(floatN *r1, floatN r2, floatN *r3, int m4, int *sig) \
28 { \
29 int cc; \
30 \
31 asm(/* Make the initial CC predictable for suppression tests */ \
32 "xr %[sig],%[sig]\n" \
33 #name " %[r1],%[r3],%[r2],%[m4]\n" \
34 "ipm %[cc]\n" \
35 "srl %[cc],28" \
36 /* \
37 * Use earlyclobbers to prevent the compiler from reusing floating \
38 * point registers. This instruction doesn't like it. \
39 */ \
40 : [r1] "+&f" (*r1), [r3] "+&f" (*r3), [sig] "=r" (*sig), [cc] "=d" (cc)\
41 : [r2] "f" (r2), [m4] "i" (m4) \
42 : "cc"); \
43 \
44 return cc; \
45 }
46
47 DIVIDE_TO_INTEGER(diebr, float)
48 DIVIDE_TO_INTEGER(didbr, double)
49
50 #define TEST_DIVIDE_TO_INTEGER(name, intN, int_fmt, floatN, float_fmt) \
51 static inline __attribute__((__always_inline__)) int \
52 test_ ## name(unsigned intN r1i, unsigned intN r2i, int m4, int fpc, \
53 unsigned intN r1o, unsigned intN r3o, int cco, unsigned int fpco,\
54 int sigo) \
55 { \
56 union { \
57 floatN f; \
58 unsigned intN i; \
59 } r1, r2, r3; \
60 int cc, err = 0, sig; \
61 \
62 r1.i = r1i; \
63 r2.i = r2i; \
64 r3.i = 0x12345678; \
65 printf("[ RUN ] %" float_fmt "(0x%" int_fmt \
66 ") / %" float_fmt "(0x%" int_fmt ")\n", r1.f, r1.i, r2.f, r2.i); \
67 asm volatile("sfpc %[fpc]" : : [fpc] "r" (fpc)); \
68 cc = name(&r1.f, r2.f, &r3.f, m4, &sig); \
69 asm volatile("stfpc %[fpc]" : [fpc] "=Q" (fpc)); \
70 if (r1.i != r1o) { \
71 printf("[ FAILED ] remainder 0x%" int_fmt \
72 " != expected 0x%" int_fmt "\n", r1.i, r1o); \
73 err += 1; \
74 } \
75 if (r3.i != r3o) { \
76 printf("[ FAILED ] quotient 0x%" int_fmt \
77 " != expected 0x%" int_fmt "\n", r3.i, r3o); \
78 err += 1; \
79 } \
80 if (cc != cco) { \
81 printf("[ FAILED ] cc %d != expected %d\n", cc, cco); \
82 err += 1; \
83 } \
84 if (fpc != fpco) { \
85 printf("[ FAILED ] fpc 0x%x != expected 0x%x\n", fpc, fpco); \
86 err += 1; \
87 } \
88 if (sig != sigo) { \
89 printf("[ FAILED ] signal 0x%x != expected 0x%x\n", sig, sigo); \
90 err += 1; \
91 } \
92 \
93 return err; \
94 }
95
96 TEST_DIVIDE_TO_INTEGER(diebr, int, "x", float, "f")
97 TEST_DIVIDE_TO_INTEGER(didbr, long, "lx", double, "lf")
98
99 int main(void)
100 {
101 struct sigaction act = {
102 .sa_sigaction = sigfpe_handler,
103 .sa_flags = SA_SIGINFO,
104 };
105 int err = 0;
106
107 /* Set up SIG handler */
108 if (sigaction(SIGFPE, &act, NULL)) {
109 printf("[ FAILED ] sigaction(SIGFPE) failed\n");
110 return EXIT_FAILURE;
111 }
112
113 /* 451 / 460 */
114 err += test_diebr(0x43e1f1f1, 0x43e61616, 7, 0,
115 0x43e1f1f1, 0, 0, 0, 0);
116
117 /* 480 / 0 */
118 err += test_diebr(0x43f00000, 0, 0, 0,
119 0x7fc00000, 0x7fc00000, 1, 0x800000, 0);
120
121 /* QNaN / QNaN */
122 err += test_diebr(0xffffffff, 0xffffffff, 0, 0,
123 0xffffffff, 0xffffffff, 1, 0, 0);
124
125 /* -2.08E-8 / -2.08E-8 */
126 err += test_diebr(0xb2b2b2b2, 0xb2b2b2b2, 0, 0,
127 0x80000000, 0x3f800000, 0, 0, 0);
128
129 /*
130 * Test partial remainder without quotient scaling (cc2).
131 *
132 * a = 12401981 / 268435456
133 * b = -5723991 / 72057594037927936
134 * q = a / b = -3329131425038336 / 5723991 =~ -581610178.1
135 * n = round(q, float32, nearest_even) = -581610176
136 * r_precise = a - b * n = 189155 / 1125899906842624
137 * r = round(r_precise, float32, nearest_even) = r_precise
138 */
139 err += test_diebr(0x3d3d3d3d, 0xaeaeaeae, 0, 0,
140 0x2f38b8c0, 0xce0aaaab, 2, 0, 0);
141
142 /* 1.07E-31 / 2.19 */
143 err += test_diebr(0x0c0c0c0c, 0x400c0c0c, 6, 0,
144 0xc00c0c0c, 0x3f800000, 0, 0x80000, 0);
145
146 /*
147 * Test partial remainder with quotient scaling (cc3).
148 *
149 * a = 298343530578310714772108083200
150 * b = -592137/10384593717069655257060992658440192
151 * q = a / b
152 * = -1032725451057301340137043014721780674141077289604872315653324800 /
153 * 197379
154 * =~ -5232195173029052432817285601415452880707052369324357280426.6
155 * n = round(q, float32, nearest_even)
156 * = -5232194943010009439437691768433469154159343131709361094656
157 * n / 2^192 = -6992213 / 8388608
158 * r_precise = a - b * n = 13115851209189604982784
159 * r = round(r_precise, float32, nearest_even) = r_precise
160 */
161 err += test_diebr(0x7070ffff, 0x90909090, 0, 0,
162 0x6431c0c0, 0xbf5562aa, 3, 0, 0);
163
164 /*
165 * Test large, but representable quotient.
166 *
167 * a = -12040119 / 549755813888
168 * b = 1 / 38685626227668133590597632
169 * q = a / b = -847248053779631702016
170 * n = round(q, float32, to_odd) = q
171 * r_precise = a - b * n = -0
172 * r = round(r_precise, float32, nearest_even) = -0
173 */
174 err += test_diebr(0xb7b7b7b7, 0x15000000, 7, 0,
175 0x80000000, 0xe237b7b7, 0, 0, 0);
176
177 /* 0 / 0 */
178 err += test_diebr(0, 0, 1, 0,
179 0x7fc00000, 0x7fc00000, 1, 0x800000, 0);
180
181 /* 4.3E-33 / -2.08E-8 with SIGFPE */
182 err += test_diebr(0x09b2b2b2, 0xb2b2b2b2, 0, 0xfc000007,
183 0xb2b2b2b1, 0xbf800000, 0, 0xfc000807, SIGFPE);
184
185 /*
186 * Test tiny remainder scaling when FPC Underflow Mask is set.
187 *
188 * 1.19E-39 / -1.28E-9 = { r = 1.19E-39 * 2^192, n = -0 }
189 */
190 err += test_diebr(0x000d0100, 0xb0b0b0b0, 6, 0xfc000000,
191 0x5ed01000, 0x80000000, 0, 0xfc001000, SIGFPE);
192
193 /*
194 * Test "inexact and incremented" DXC.
195 *
196 * a = 53555504
197 * b = -520849213389117849600
198 * q = a / b = -3347219 / 32553075836819865600
199 * n = round(q, float32, to_odd) = -1
200 * r_precise = a - b * n = -520849213389064294096
201 * r = round(r_precise, float32, to_odd) = -520849213389117849600
202 * abs(r) - abs(r_precise) = 53555504
203 */
204 err += test_diebr(0x4c4c4c4c, 0xe1e1e1e1, 0, 0xfc000007,
205 0xe1e1e1e1, 0xbf800000, 0, 0xfc000c07, SIGFPE);
206
207 /* 0 / 0 with SIGFPE */
208 err += test_diebr(0, 0, 0, 0xfc000007,
209 0, 0x12345678, 0, 0xfc008007, SIGFPE);
210
211 /* 5.76E-16 / 5.39E+34 */
212 err += test_diebr(0x26262626, 0x79262626, 6, 0,
213 0xf9262626, 0x3f800000, 0, 0x80000, 0);
214
215 /* -4.97E+17 / 2.03E-38 */
216 err += test_diebr(0xdcdcdcdc, 0x00dcdcdc, 7, 0xfc000000,
217 0x80000000, 0xbb800000, 1, 0xfc000000, 0);
218
219 /* -1.23E+17 / SNaN */
220 err += test_diebr(0xdbdb240b, 0xffac73ff, 4, 0,
221 0xffec73ff, 0xffec73ff, 1, 0x800000, 0);
222
223 /* 2.34E-38 / 3.27E-33 with SIGFPE */
224 err += test_diebr(0x00ff0987, 0x0987c6f6, 6, 0x08000000,
225 0x8987c6b6, 0x3f800000, 0, 0x8000800, SIGFPE);
226
227 /* -5.93E+11 / -2.7E+4 */
228 err += test_diebr(0xd30a0040, 0xc6d30a00, 0, 0xc4000000,
229 0xc74a4400, 0x4ba766c6, 2, 0xc4000000, 0);
230
231 /* 9.86E-32 / -inf */
232 err += test_diebr(0x0c000029, 0xff800000, 0, 0,
233 0xc000029, 0x80000000, 0, 0, 0);
234
235 /* QNaN / SNaN */
236 err += test_diebr(0xffff94ff, 0xff94ff24, 4, 7,
237 0xffd4ff24, 0xffd4ff24, 1, 0x800007, 0);
238
239 /* 2.8E-43 / -inf */
240 err += test_diebr(0x000000c8, 0xff800000, 0, 0x7c000007,
241 0x000000c8, 0x80000000, 0, 0x7c000007, 0);
242
243 /* -1.7E+38 / -inf */
244 err += test_diebr(0xff00003d, 0xff800000, 0, 0,
245 0xff00003d, 0, 0, 0, 0);
246
247 /* 1.94E-304 / 1.94E-304 */
248 err += test_didbr(0x00e100e100e100e1, 0x00e100e100e100e1, 0, 1,
249 0, 0x3ff0000000000000, 0, 1, 0);
250
251 /* 4.82E-299 / 5.29E-308 */
252 err += test_didbr(0x0200230200230200, 0x0023020023020023, 0, 0,
253 0x8001a017d247b3f4, 0x41cb2aa05f000000, 0, 0, 0);
254
255 /* -1.38E-75 / -3.77E+208 */
256 err += test_didbr(0xb063eb3d63b063eb, 0xeb3d63b063eb3d63, 3, 0xe8000000,
257 0x6b3d63b063eb3d63, 0x3ff0000000000000, 0, 0xe8000c00,
258 SIGFPE);
259
260 /* 4.78E-299 / 6.88E-315 */
261 err += test_didbr(0x0200000000000000, 0x0000000053020000, 0, 0,
262 0x8000000020820000, 0x4338ac20dd47c6c1, 0, 0, 0);
263
264 return err ? EXIT_FAILURE : EXIT_SUCCESS;
265 }