bcdsub.c (5095B)
1 #include <assert.h> 2 #include <unistd.h> 3 #include <signal.h> 4 #include <stdint.h> 5 6 #define CRF_LT (1 << 3) 7 #define CRF_GT (1 << 2) 8 #define CRF_EQ (1 << 1) 9 #define CRF_SO (1 << 0) 10 #define UNDEF 0 11 12 #ifdef __has_builtin 13 #if !__has_builtin(__builtin_bcdsub) 14 #define NO_BUILTIN_BCDSUB 15 #endif 16 #endif 17 18 #ifdef NO_BUILTIN_BCDSUB 19 #define BCDSUB(T, A, B, PS) \ 20 ".long 4 << 26 | (" #T ") << 21 | (" #A ") << 16 | (" #B ") << 11" \ 21 " | 1 << 10 | (" #PS ") << 9 | 65\n\t" 22 #else 23 #define BCDSUB(T, A, B, PS) "bcdsub. " #T ", " #A ", " #B ", " #PS "\n\t" 24 #endif 25 26 #define TEST(AH, AL, BH, BL, PS, TH, TL, CR6) \ 27 do { \ 28 int cr = 0; \ 29 uint64_t th, tl; \ 30 /* \ 31 * Use GPR pairs to load the VSR values and place the resulting VSR and\ 32 * CR6 in th, tl, and cr. Note that we avoid newer instructions (e.g., \ 33 * mtvsrdd/mfvsrld) so we can run this test on POWER8 machines. \ 34 */ \ 35 asm ("mtvsrd 32, %3\n\t" \ 36 "mtvsrd 33, %4\n\t" \ 37 "xxmrghd 32, 32, 33\n\t" \ 38 "mtvsrd 33, %5\n\t" \ 39 "mtvsrd 34, %6\n\t" \ 40 "xxmrghd 33, 33, 34\n\t" \ 41 BCDSUB(0, 0, 1, PS) \ 42 "mfocrf %0, 0b10\n\t" \ 43 "mfvsrd %1, 32\n\t" \ 44 "xxswapd 32, 32\n\t" \ 45 "mfvsrd %2, 32\n\t" \ 46 : "=r" (cr), "=r" (th), "=r" (tl) \ 47 : "r" (AH), "r" (AL), "r" (BH), "r" (BL) \ 48 : "v0", "v1", "v2"); \ 49 if (TH != UNDEF || TL != UNDEF) { \ 50 assert(tl == TL); \ 51 assert(th == TH); \ 52 } \ 53 assert((cr >> 4) == CR6); \ 54 } while (0) 55 56 /* 57 * Unbounded result is equal to zero: 58 * sign = (PS) ? 0b1111 : 0b1100 59 * CR6 = 0b0010 60 */ 61 void test_bcdsub_eq(void) 62 { 63 /* maximum positive BCD value */ 64 TEST(0x9999999999999999, 0x999999999999999c, 65 0x9999999999999999, 0x999999999999999c, 66 0, 0x0, 0xc, CRF_EQ); 67 TEST(0x9999999999999999, 0x999999999999999c, 68 0x9999999999999999, 0x999999999999999c, 69 1, 0x0, 0xf, CRF_EQ); 70 } 71 72 /* 73 * Unbounded result is greater than zero: 74 * sign = (PS) ? 0b1111 : 0b1100 75 * CR6 = (overflow) ? 0b0101 : 0b0100 76 */ 77 void test_bcdsub_gt(void) 78 { 79 /* maximum positive and negative one BCD values */ 80 TEST(0x9999999999999999, 0x999999999999999c, 0x0, 0x1d, 0, 81 0x0, 0xc, (CRF_GT | CRF_SO)); 82 TEST(0x9999999999999999, 0x999999999999999c, 0x0, 0x1d, 1, 83 0x0, 0xf, (CRF_GT | CRF_SO)); 84 85 TEST(0x9999999999999999, 0x999999999999998c, 0x0, 0x1d, 0, 86 0x9999999999999999, 0x999999999999999c, CRF_GT); 87 TEST(0x9999999999999999, 0x999999999999998c, 0x0, 0x1d, 1, 88 0x9999999999999999, 0x999999999999999f, CRF_GT); 89 } 90 91 /* 92 * Unbounded result is less than zero: 93 * sign = 0b1101 94 * CR6 = (overflow) ? 0b1001 : 0b1000 95 */ 96 void test_bcdsub_lt(void) 97 { 98 /* positive zero and positive one BCD values */ 99 TEST(0x0, 0xc, 0x0, 0x1c, 0, 0x0, 0x1d, CRF_LT); 100 TEST(0x0, 0xc, 0x0, 0x1c, 1, 0x0, 0x1d, CRF_LT); 101 102 /* maximum negative and positive one BCD values */ 103 TEST(0x9999999999999999, 0x999999999999999d, 0x0, 0x1c, 0, 104 0x0, 0xd, (CRF_LT | CRF_SO)); 105 TEST(0x9999999999999999, 0x999999999999999d, 0x0, 0x1c, 1, 106 0x0, 0xd, (CRF_LT | CRF_SO)); 107 } 108 109 void test_bcdsub_invalid(void) 110 { 111 TEST(0x0, 0x1c, 0x0, 0xf00, 0, UNDEF, UNDEF, CRF_SO); 112 TEST(0x0, 0x1c, 0x0, 0xf00, 1, UNDEF, UNDEF, CRF_SO); 113 114 TEST(0x0, 0xf00, 0x0, 0x1c, 0, UNDEF, UNDEF, CRF_SO); 115 TEST(0x0, 0xf00, 0x0, 0x1c, 1, UNDEF, UNDEF, CRF_SO); 116 117 TEST(0x0, 0xbad, 0x0, 0xf00, 0, UNDEF, UNDEF, CRF_SO); 118 TEST(0x0, 0xbad, 0x0, 0xf00, 1, UNDEF, UNDEF, CRF_SO); 119 } 120 121 int main(void) 122 { 123 struct sigaction action; 124 125 action.sa_handler = _exit; 126 sigaction(SIGABRT, &action, NULL); 127 128 test_bcdsub_eq(); 129 test_bcdsub_gt(); 130 test_bcdsub_lt(); 131 test_bcdsub_invalid(); 132 133 return 0; 134 }