1 /* fpe.c 1.2 89/05/05 */ 2 3 #include "../tahoe/psl.h" 4 #include "../tahoe/reg.h" 5 #include "../tahoe/pte.h" 6 #include "../tahoe/mtpr.h" 7 #include "../tahoemath/Kfp.h" 8 9 #include "param.h" 10 #include "systm.h" 11 #include "user.h" 12 #include "proc.h" 13 #include "seg.h" 14 #include "acct.h" 15 #include "kernel.h" 16 17 /* 18 * Floating point emulation support. 19 */ 20 extern float Kcvtlf(), Kaddf(), Ksubf(), Kmulf(), Kdivf(); 21 extern double Kcvtld(), Kaddd(), Ksubd(), Kmuld(), Kdivd(); 22 extern float Ksinf(), Kcosf(), Katanf(), Klogf(), Ksqrtf(), Kexpf(); 23 24 #define OP(dop) ((dop) &~ 01) /* precision-less version of opcode */ 25 #define isdouble(op) ((op) & 01) /* is opcode double or float */ 26 27 struct fpetab { 28 int fpe_op; /* base opcode emulating */ 29 float (*fpe_ffunc)(); /* float version of op */ 30 double (*fpe_dfunc)(); /* double version of op */ 31 } fpetab[] = { 32 { OP(CVLD), Kcvtlf, Kcvtld }, 33 { OP(ADDD), Kaddf, Kaddd }, 34 { OP(SUBD), Ksubf, Ksubd }, 35 { OP(MULD), Kmulf, Kmuld }, 36 { OP(DIVD), Kdivf, Kdivd }, 37 { SINF, Ksinf, 0 }, 38 { COSF, Kcosf, 0 }, 39 { ATANF, Katanf, 0 }, 40 { LOGF, Klogf, 0 }, 41 { SQRTF, Ksqrtf, 0 }, 42 { EXPF, Kexpf, 0 }, 43 }; 44 #define NFPETAB (sizeof (fpetab) / sizeof (fpetab[0])) 45 46 /* 47 * Emulate the FP opcode. Update psl as necessary. 48 * If OK, set opcode to 0, else to the FP exception #. 49 * Not all parameter longwords are relevant, depends on opcode. 50 * 51 * The entry mask is set by locore.s so ALL registers are saved. 52 * This enables FP opcodes to change user registers on return. 53 */ 54 /* WARNING!!!! THIS CODE MUST NOT PRODUCE ANY FLOATING POINT EXCEPTIONS */ 55 /*ARGSUSED*/ 56 fpemulate(hfsreg, acc_most, acc_least, dbl, op_most, op_least, opcode, pc, psl) 57 { 58 int r0, r1; /* must reserve space */ 59 register int *locr0 = ((int *)&psl)-PS; 60 register struct fpetab *fp; 61 int hfs = 0; /* returned data about exceptions */ 62 int type; /* opcode type, FLOAT or DOUBLE */ 63 union { float ff; int fi; } f_res; 64 union { double dd; int di[2]; } d_res; 65 66 #ifdef lint 67 r0 = 0; r0 = r0; r1 = 0; r1 = r1; 68 #endif 69 type = isdouble(opcode) ? DOUBLE : FLOAT; 70 for (fp = fpetab; fp < &fpetab[NFPETAB]; fp++) 71 if ((opcode & 0xfe) == fp->fpe_op) 72 break; 73 if (type == DOUBLE) { 74 if (fp->fpe_dfunc == 0) 75 fp = &fpetab[NFPETAB]; 76 else 77 locr0[PS] &= ~PSL_DBL; 78 } 79 if (fp >= &fpetab[NFPETAB]) { 80 opcode = DIV0_EXC; /* generate SIGILL - XXX */ 81 return; 82 } 83 switch (type) { 84 85 case DOUBLE: 86 d_res.dd = (*fp->fpe_dfunc)(acc_most, acc_least, op_most, 87 op_least, &hfs); 88 if (d_res.di[0] == 0 && d_res.di[1] == 0) 89 locr0[PS] |= PSL_Z; 90 if (d_res.di[0] < 0) 91 locr0[PS] |= PSL_N; 92 break; 93 94 case FLOAT: 95 f_res.ff = (*fp->fpe_ffunc)(acc_most, acc_least, op_most, 96 op_least, &hfs); 97 if (f_res.fi == 0) 98 locr0[PS] |= PSL_Z; 99 if (f_res.fi == 0) 100 locr0[PS] |= PSL_N; 101 break; 102 } 103 if (hfs & HFS_OVF) { 104 locr0[PS] |= PSL_V; /* turn on overflow bit */ 105 #ifdef notdef 106 if (locr0[PS] & PSL_IV) { /* overflow enabled? */ 107 #endif 108 opcode = OVF_EXC; 109 u.u_error = (hfs & HFS_DOM) ? EDOM : ERANGE; 110 return; 111 #ifdef notdef 112 } 113 #endif 114 } else if (hfs & HFS_UNDF) { 115 if (locr0[PS] & PSL_FU) { /* underflow enabled? */ 116 opcode = UNDF_EXC; 117 u.u_error = (hfs & HFS_DOM) ? EDOM : ERANGE; 118 return; 119 } 120 } else if (hfs & HFS_DIVZ) { 121 opcode = DIV0_EXC; 122 return; 123 } else if (hfs & HFS_DOM) 124 u.u_error = EDOM; 125 else if (hfs & HFS_RANGE) 126 u.u_error = ERANGE; 127 switch (type) { 128 129 case DOUBLE: 130 if (hfs & (HFS_OVF|HFS_UNDF)) { 131 d_res.dd = 0.0; 132 locr0[PS] |= PSL_Z; 133 } 134 mvtodacc(d_res.di[0], d_res.di[1], &acc_most); 135 break; 136 137 case FLOAT: 138 if (hfs & (HFS_OVF|HFS_UNDF)) { 139 f_res.ff = 0.0; 140 locr0[PS] |= PSL_Z; 141 } 142 mvtofacc(f_res.ff, &acc_most); 143 break; 144 } 145 opcode = 0; 146 } 147