/* * errors.c * * The error handling functions for wm-FPU-emu * * * Copyright (C) 1992, 1993 W. Metzenthen, 22 Parker St, Ormond, * Vic 3163, Australia. * E-mail apm233m@vaxc.cc.monash.edu.au * All rights reserved. * * This copyright notice covers the redistribution and use of the * FPU emulator developed by W. Metzenthen. It covers only its use * in the 386BSD operating system. Any other use is not permitted * under this copyright. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must include information specifying * that source code for the emulator is freely available and include * either: * a) an offer to provide the source code for a nominal distribution * fee, or * b) list at least two alternative methods whereby the source * can be obtained, e.g. a publically accessible bulletin board * and an anonymous ftp site from which the software can be * downloaded. * 3. All advertising materials specifically mentioning features or use of * this emulator must acknowledge that it was developed by W. Metzenthen. * 4. The name of W. Metzenthen may not be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL * W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * * $Id:$ * */ /*---------------------------------------------------------------------------+ | Note: | | The file contains code which accesses user memory. | | Emulator static data may change when user memory is accessed, due to | | other processes using the emulator while swapping is in progress. | +---------------------------------------------------------------------------*/ #include "param.h" #include "proc.h" #include "machine/cpu.h" #include "machine/pcb.h" #include "fpu_emu.h" #include "fpu_system.h" #include "exception.h" #include "status_w.h" #include "control_w.h" #include "reg_constant.h" #include "version.h" /* */ #undef PRINT_MESSAGES /* */ void Un_impl(void) { unsigned char byte1, FPU_modrm; REENTRANT_CHECK(OFF); byte1 = fubyte((unsigned char *) FPU_ORIG_EIP); FPU_modrm = fubyte(1 + (unsigned char *) FPU_ORIG_EIP); printf("Unimplemented FPU Opcode at eip=%p : %02x ", FPU_ORIG_EIP, byte1); if (FPU_modrm >= 0300) printf("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7); else printf("/%d\n", (FPU_modrm >> 3) & 7); REENTRANT_CHECK(ON); EXCEPTION(EX_Invalid); } void emu_printall() { int i; static char *tag_desc[] = {"Valid", "Zero", "ERROR", "ERROR", "DeNorm", "Inf", "NaN", "Empty"}; unsigned char byte1, FPU_modrm; REENTRANT_CHECK(OFF); byte1 = fubyte((unsigned char *) FPU_ORIG_EIP); FPU_modrm = fubyte(1 + (unsigned char *) FPU_ORIG_EIP); #ifdef DEBUGGING if (status_word & SW_Backward) printf("SW: backward compatibility\n"); if (status_word & SW_C3) printf("SW: condition bit 3\n"); if (status_word & SW_C2) printf("SW: condition bit 2\n"); if (status_word & SW_C1) printf("SW: condition bit 1\n"); if (status_word & SW_C0) printf("SW: condition bit 0\n"); if (status_word & SW_Summary) printf("SW: exception summary\n"); if (status_word & SW_Stack_Fault) printf("SW: stack fault\n"); if (status_word & SW_Precision) printf("SW: loss of precision\n"); if (status_word & SW_Underflow) printf("SW: underflow\n"); if (status_word & SW_Overflow) printf("SW: overflow\n"); if (status_word & SW_Zero_Div) printf("SW: divide by zero\n"); if (status_word & SW_Denorm_Op) printf("SW: denormalized operand\n"); if (status_word & SW_Invalid) printf("SW: invalid operation\n"); #endif /* DEBUGGING */ status_word = status_word & ~SW_Top; status_word |= (top & 7) << SW_Top_Shift; printf("At %p: %02x ", FPU_ORIG_EIP, byte1); if (FPU_modrm >= 0300) printf("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7); else printf("/%d, mod=%d rm=%d\n", (FPU_modrm >> 3) & 7, (FPU_modrm >> 6) & 3, FPU_modrm & 7); printf(" SW: b=%d st=%d es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n", status_word & 0x8000 ? 1 : 0, /* busy */ (status_word & 0x3800) >> 11, /* stack top pointer */ status_word & 0x80 ? 1 : 0, /* Error summary status */ status_word & 0x40 ? 1 : 0, /* Stack flag */ status_word & SW_C3 ? 1 : 0, status_word & SW_C2 ? 1 : 0, /* cc */ status_word & SW_C1 ? 1 : 0, status_word & SW_C0 ? 1 : 0, /* cc */ status_word & SW_Precision ? 1 : 0, status_word & SW_Underflow ? 1 : 0, status_word & SW_Overflow ? 1 : 0, status_word & SW_Zero_Div ? 1 : 0, status_word & SW_Denorm_Op ? 1 : 0, status_word & SW_Invalid ? 1 : 0); printf(" CW: ic=%d rc=%d%d pc=%d%d iem=%d ef=%d%d%d%d%d%d\n", control_word & 0x1000 ? 1 : 0, (control_word & 0x800) >> 11, (control_word & 0x400) >> 10, (control_word & 0x200) >> 9, (control_word & 0x100) >> 8, control_word & 0x80 ? 1 : 0, control_word & SW_Precision ? 1 : 0, control_word & SW_Underflow ? 1 : 0, control_word & SW_Overflow ? 1 : 0, control_word & SW_Zero_Div ? 1 : 0, control_word & SW_Denorm_Op ? 1 : 0, control_word & SW_Invalid ? 1 : 0); for (i = 0; i < 8; i++) { FPU_REG *r = &st(i); switch (r->tag) { case TW_Empty: continue; break; case TW_Zero: printf("st(%d) %c .0000 0000 0000 0000 ", i, r->sign ? '-' : '+'); break; case TW_Valid: case TW_NaN: case TW_Denormal: case TW_Infinity: printf("st(%d) %c .%04x %04x %04x %04x e%+-6d ", i, r->sign ? '-' : '+', (long) (r->sigh >> 16), (long) (r->sigh & 0xFFFF), (long) (r->sigl >> 16), (long) (r->sigl & 0xFFFF), r->exp - EXP_BIAS + 1); break; default: printf("Whoops! Error in errors.c "); break; } printf("%s\n", tag_desc[(int) (unsigned) r->tag]); } printf("[data] %c .%04x %04x %04x %04x e%+-6d ", FPU_loaded_data.sign ? '-' : '+', (long) (FPU_loaded_data.sigh >> 16), (long) (FPU_loaded_data.sigh & 0xFFFF), (long) (FPU_loaded_data.sigl >> 16), (long) (FPU_loaded_data.sigl & 0xFFFF), FPU_loaded_data.exp - EXP_BIAS + 1); printf("%s\n", tag_desc[(int) (unsigned) FPU_loaded_data.tag]); REENTRANT_CHECK(ON); } static struct { int type; char *name; } exception_names[] = { { EX_StackOver, "stack overflow" }, { EX_StackUnder, "stack underflow" }, { EX_Precision, "loss of precision" }, { EX_Underflow, "underflow" }, { EX_Overflow, "overflow" }, { EX_ZeroDiv, "divide by zero" }, { EX_Denormal, "denormalized operand" }, { EX_Invalid, "invalid operation" }, { EX_INTERNAL, "INTERNAL BUG in " FPU_VERSION }, { 0, NULL } }; /* EX_INTERNAL is always given with a code which indicates where the error was detected. Internal error types: 0x14 in e14.c 0x1nn in a *.c file: 0x101 in reg_add_sub.c 0x102 in reg_mul.c 0x103 in poly_sin.c 0x104 in poly_tan.c 0x105 in reg_mul.c 0x106 in reg_mov.c 0x107 in fpu_trig.c 0x108 in reg_compare.c 0x109 in reg_compare.c 0x110 in reg_add_sub.c 0x111 in interface.c 0x112 in fpu_trig.c 0x113 in reg_add_sub.c 0x114 in reg_ld_str.c 0x115 in fpu_trig.c 0x116 in fpu_trig.c 0x117 in fpu_trig.c 0x118 in fpu_trig.c 0x119 in fpu_trig.c 0x120 in poly_atan.c 0x121 in reg_compare.c 0x122 in reg_compare.c 0x123 in reg_compare.c 0x2nn in an *.s file: 0x201 in reg_u_add.S 0x202 in reg_u_div.S 0x203 in reg_u_div.S 0x204 in reg_u_div.S 0x205 in reg_u_mul.S 0x206 in reg_u_sub.S 0x207 in wm_sqrt.S 0x208 in reg_div.S 0x209 in reg_u_sub.S 0x210 in reg_u_sub.S 0x211 in reg_u_sub.S 0x212 in reg_u_sub.S 0x213 in wm_sqrt.S 0x214 in wm_sqrt.S 0x215 in wm_sqrt.S 0x216 in reg_round.S 0x217 in reg_round.S 0x218 in reg_round.S */ void exception(int n) { int i, int_type; int_type = 0; /* Needed only to stop compiler warnings */ if (n & EX_INTERNAL) { int_type = n - EX_INTERNAL; n = EX_INTERNAL; /* Set lots of exception bits! */ status_word |= (SW_Exc_Mask | SW_Summary | FPU_BUSY); } else { /* Extract only the bits which we use to set the status word */ n &= (SW_Exc_Mask); /* Set the corresponding exception bit */ status_word |= n; if (status_word & ~control_word & CW_Exceptions) status_word |= SW_Summary; if (n & (SW_Stack_Fault | EX_Precision)) { if (!(n & SW_C1)) /* This bit distinguishes over- from underflow * for a stack fault, and roundup from * round-down for precision loss. */ status_word &= ~SW_C1; } } REENTRANT_CHECK(OFF); if ((~control_word & n & CW_Exceptions) || (n == EX_INTERNAL)) { #ifdef PRINT_MESSAGES /* My message from the sponsor */ printf(FPU_VERSION " " __DATE__ " (C) W. Metzenthen.\n"); #endif /* PRINT_MESSAGES */ /* Get a name string for error reporting */ for (i = 0; exception_names[i].type; i++) if ((exception_names[i].type & n) == exception_names[i].type) break; if (exception_names[i].type) { #ifdef PRINT_MESSAGES printf("FP Exception: %s!\n", exception_names[i].name); #endif /* PRINT_MESSAGES */ } else printf("FP emulator: Unknown Exception: 0x%04x!\n", n); if (n == EX_INTERNAL) { printf("FP emulator: Internal error type 0x%04x\n", int_type); emu_printall(); } #ifdef PRINT_MESSAGES else emu_printall(); #endif /* PRINT_MESSAGES */ /* The 80486 generates an interrupt on the next non-control * FPU instruction. So we need some means of flagging it. We * use the ES (Error Summary) bit for this, assuming that this * is the way a real FPU does it (until I can check it out), * if not, then some method such as the following kludge might * be needed. */ /* regs[0].tag |= TW_FPU_Interrupt; */ } REENTRANT_CHECK(ON); #ifdef __DEBUG__ math_abort(SIGFPE); #endif /* __DEBUG__ */ } /* Real operation attempted on two operands, one a NaN */ void real_2op_NaN(FPU_REG * a, FPU_REG * b, FPU_REG * dest) { FPU_REG *x; int signalling; x = a; if (a->tag == TW_NaN) { if (b->tag == TW_NaN) { signalling = !(a->sigh & b->sigh & 0x40000000); /* find the "larger" */ if (*(long long *) &(a->sigl) < *(long long *) &(b->sigl)) x = b; } else { /* return the quiet version of the NaN in a */ signalling = !(a->sigh & 0x40000000); } } else #ifdef PARANOID if (b->tag == TW_NaN) #endif /* PARANOID */ { signalling = !(b->sigh & 0x40000000); x = b; } #ifdef PARANOID else { signalling = 0; EXCEPTION(EX_INTERNAL | 0x113); x = &CONST_QNaN; } #endif /* PARANOID */ if (!signalling) { if (!(x->sigh & 0x80000000)) /* pseudo-NaN ? */ x = &CONST_QNaN; reg_move(x, dest); return; } if (control_word & CW_Invalid) { /* The masked response */ if (!(x->sigh & 0x80000000)) /* pseudo-NaN ? */ x = &CONST_QNaN; reg_move(x, dest); /* ensure a Quiet NaN */ dest->sigh |= 0x40000000; } EXCEPTION(EX_Invalid); return; } /* Invalid arith operation on Valid registers */ void arith_invalid(FPU_REG * dest) { if (control_word & CW_Invalid) { /* The masked response */ reg_move(&CONST_QNaN, dest); } EXCEPTION(EX_Invalid); return; } /* Divide a finite number by zero */ void divide_by_zero(int sign, FPU_REG * dest) { if (control_word & CW_ZeroDiv) { /* The masked response */ reg_move(&CONST_INF, dest); dest->sign = (unsigned char) sign; } EXCEPTION(EX_ZeroDiv); return; } /* This may be called often, so keep it lean */ void set_precision_flag_up(void) { if (control_word & CW_Precision) status_word |= (SW_Precision | SW_C1); /* The masked response */ else exception(EX_Precision | SW_C1); } /* This may be called often, so keep it lean */ void set_precision_flag_down(void) { if (control_word & CW_Precision) { /* The masked response */ status_word &= ~SW_C1; status_word |= SW_Precision; } else exception(EX_Precision); } int denormal_operand(void) { if (control_word & CW_Denormal) { /* The masked response */ status_word |= SW_Denorm_Op; return 0; } else { exception(EX_Denormal); return 1; } } void arith_overflow(FPU_REG * dest) { if (control_word & CW_Overflow) { char sign; /* The masked response */ /* **** The response here depends upon the rounding mode */ sign = dest->sign; reg_move(&CONST_INF, dest); dest->sign = sign; } else { /* Subtract the magic number from the exponent */ dest->exp -= (3 * (1 << 13)); } /* By definition, precision is lost. It appears that the roundup bit * (C1) is also set by convention. */ EXCEPTION(EX_Overflow | EX_Precision | SW_C1); return; } void arith_underflow(FPU_REG * dest) { if (control_word & CW_Underflow) { /* The masked response */ if (dest->exp <= EXP_UNDER - 63) reg_move(&CONST_Z, dest); } else { /* Add the magic number to the exponent */ dest->exp += (3 * (1 << 13)); } EXCEPTION(EX_Underflow); return; } void stack_overflow(void) { if (control_word & CW_Invalid) { /* The masked response */ top--; reg_move(&CONST_QNaN, FPU_st0_ptr = &st(0)); } EXCEPTION(EX_StackOver); return; } void stack_underflow(void) { if (control_word & CW_Invalid) { /* The masked response */ reg_move(&CONST_QNaN, FPU_st0_ptr); } EXCEPTION(EX_StackUnder); return; } void stack_underflow_i(int i) { if (control_word & CW_Invalid) { /* The masked response */ reg_move(&CONST_QNaN, &(st(i))); } EXCEPTION(EX_StackUnder); return; } void stack_underflow_pop(int i) { if (control_word & CW_Invalid) { /* The masked response */ reg_move(&CONST_QNaN, &(st(i))); pop(); } EXCEPTION(EX_StackUnder); return; }