/*---------------------------------------------------------------------------+ | errors.c | | | | The error handling functions for wm-FPU-emu | | | | Copyright (C) 1992,1993,1994,1996 | | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | | E-mail billm@jacobi.maths.monash.edu.au | | | | | +---------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------+ | 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 <linux/signal.h> #include <asm/uaccess.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 /* */ #if 0 void Un_impl(void) { u_char byte1, FPU_modrm; unsigned long address = FPU_ORIG_EIP; RE_ENTRANT_CHECK_OFF; /* No need to check access_ok(), we have previously fetched these bytes. */ printk("Unimplemented FPU Opcode at eip=%p : ", (void __user *)address); if (FPU_CS == __USER_CS) { while (1) { FPU_get_user(byte1, (u_char __user *) address); if ((byte1 & 0xf8) == 0xd8) break; printk("[%02x]", byte1); address++; } printk("%02x ", byte1); FPU_get_user(FPU_modrm, 1 + (u_char __user *) address); if (FPU_modrm >= 0300) printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7); else printk("/%d\n", (FPU_modrm >> 3) & 7); } else { printk("cs selector = %04x\n", FPU_CS); } RE_ENTRANT_CHECK_ON; EXCEPTION(EX_Invalid); } #endif /* 0 */ /* Called for opcodes which are illegal and which are known to result in a SIGILL with a real 80486. */ void FPU_illegal(void) { math_abort(FPU_info, SIGILL); } void FPU_printall(void) { int i; static const char *tag_desc[] = { "Valid", "Zero", "ERROR", "Empty", "DeNorm", "Inf", "NaN" }; u_char byte1, FPU_modrm; unsigned long address = FPU_ORIG_EIP; RE_ENTRANT_CHECK_OFF; /* No need to check access_ok(), we have previously fetched these bytes. */ printk("At %p:", (void *)address); if (FPU_CS == __USER_CS) { #define MAX_PRINTED_BYTES 20 for (i = 0; i < MAX_PRINTED_BYTES; i++) { FPU_get_user(byte1, (u_char __user *) address); if ((byte1 & 0xf8) == 0xd8) { printk(" %02x", byte1); break; } printk(" [%02x]", byte1); address++; } if (i == MAX_PRINTED_BYTES) printk(" [more..]\n"); else { FPU_get_user(FPU_modrm, 1 + (u_char __user *) address); if (FPU_modrm >= 0300) printk(" %02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7); else printk(" /%d, mod=%d rm=%d\n", (FPU_modrm >> 3) & 7, (FPU_modrm >> 6) & 3, FPU_modrm & 7); } } else { printk("%04x\n", FPU_CS); } partial_status = status_word(); #ifdef DEBUGGING if (partial_status & SW_Backward) printk("SW: backward compatibility\n"); if (partial_status & SW_C3) printk("SW: condition bit 3\n"); if (partial_status & SW_C2) printk("SW: condition bit 2\n"); if (partial_status & SW_C1) printk("SW: condition bit 1\n"); if (partial_status & SW_C0) printk("SW: condition bit 0\n"); if (partial_status & SW_Summary) printk("SW: exception summary\n"); if (partial_status & SW_Stack_Fault) printk("SW: stack fault\n"); if (partial_status & SW_Precision) printk("SW: loss of precision\n"); if (partial_status & SW_Underflow) printk("SW: underflow\n"); if (partial_status & SW_Overflow) printk("SW: overflow\n"); if (partial_status & SW_Zero_Div) printk("SW: divide by zero\n"); if (partial_status & SW_Denorm_Op) printk("SW: denormalized operand\n"); if (partial_status & SW_Invalid) printk("SW: invalid operation\n"); #endif /* DEBUGGING */ printk(" SW: b=%d st=%d es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n", partial_status & 0x8000 ? 1 : 0, /* busy */ (partial_status & 0x3800) >> 11, /* stack top pointer */ partial_status & 0x80 ? 1 : 0, /* Error summary status */ partial_status & 0x40 ? 1 : 0, /* Stack flag */ partial_status & SW_C3 ? 1 : 0, partial_status & SW_C2 ? 1 : 0, /* cc */ partial_status & SW_C1 ? 1 : 0, partial_status & SW_C0 ? 1 : 0, /* cc */ partial_status & SW_Precision ? 1 : 0, partial_status & SW_Underflow ? 1 : 0, partial_status & SW_Overflow ? 1 : 0, partial_status & SW_Zero_Div ? 1 : 0, partial_status & SW_Denorm_Op ? 1 : 0, partial_status & SW_Invalid ? 1 : 0); printk(" 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); u_char tagi = FPU_gettagi(i); switch (tagi) { case TAG_Empty: continue; break; case TAG_Zero: case TAG_Special: tagi = FPU_Special(r); case TAG_Valid: printk("st(%d) %c .%04lx %04lx %04lx %04lx e%+-6d ", i, getsign(r) ? '-' : '+', (long)(r->sigh >> 16), (long)(r->sigh & 0xFFFF), (long)(r->sigl >> 16), (long)(r->sigl & 0xFFFF), exponent(r) - EXP_BIAS + 1); break; default: printk("Whoops! Error in errors.c: tag%d is %d ", i, tagi); continue; break; } printk("%s\n", tag_desc[(int)(unsigned)tagi]); } RE_ENTRANT_CHECK_ON; } static struct { int type; const 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 fpu_etc.c 0x1nn in a *.c file: 0x101 in reg_add_sub.c 0x102 in reg_mul.c 0x104 in poly_atan.c 0x105 in reg_mul.c 0x107 in fpu_trig.c 0x108 in reg_compare.c 0x109 in reg_compare.c 0x110 in reg_add_sub.c 0x111 in fpe_entry.c 0x112 in fpu_trig.c 0x113 in errors.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 0x125 in fpu_trig.c 0x126 in fpu_entry.c 0x127 in poly_2xm1.c 0x128 in fpu_entry.c 0x129 in fpu_entry.c 0x130 in get_address.c 0x131 in get_address.c 0x132 in get_address.c 0x133 in get_address.c 0x140 in load_store.c 0x141 in load_store.c 0x150 in poly_sin.c 0x151 in poly_sin.c 0x160 in reg_ld_str.c 0x161 in reg_ld_str.c 0x162 in reg_ld_str.c 0x163 in reg_ld_str.c 0x164 in reg_ld_str.c 0x170 in fpu_tags.c 0x171 in fpu_tags.c 0x172 in fpu_tags.c 0x180 in reg_convert.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 0x220 in reg_norm.S 0x221 in reg_norm.S 0x230 in reg_round.S 0x231 in reg_round.S 0x232 in reg_round.S 0x233 in reg_round.S 0x234 in reg_round.S 0x235 in reg_round.S 0x236 in reg_round.S 0x240 in div_Xsig.S 0x241 in div_Xsig.S 0x242 in div_Xsig.S */ asmlinkage void FPU_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! */ partial_status |= (SW_Exc_Mask | SW_Summary | SW_Backward); } else { /* Extract only the bits which we use to set the status word */ n &= (SW_Exc_Mask); /* Set the corresponding exception bit */ partial_status |= n; /* Set summary bits iff exception isn't masked */ if (partial_status & ~control_word & CW_Exceptions) partial_status |= (SW_Summary | SW_Backward); 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. */ partial_status &= ~SW_C1; } } RE_ENTRANT_CHECK_OFF; if ((~control_word & n & CW_Exceptions) || (n == EX_INTERNAL)) { #ifdef PRINT_MESSAGES /* My message from the sponsor */ printk(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 printk("FP Exception: %s!\n", exception_names[i].name); #endif /* PRINT_MESSAGES */ } else printk("FPU emulator: Unknown Exception: 0x%04x!\n", n); if (n == EX_INTERNAL) { printk("FPU emulator: Internal error type 0x%04x\n", int_type); FPU_printall(); } #ifdef PRINT_MESSAGES else FPU_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. */ } RE_ENTRANT_CHECK_ON; #ifdef __DEBUG__ math_abort(FPU_info, SIGFPE); #endif /* __DEBUG__ */ } /* Real operation attempted on a NaN. */ /* Returns < 0 if the exception is unmasked */ int real_1op_NaN(FPU_REG *a) { int signalling, isNaN; isNaN = (exponent(a) == EXP_OVER) && (a->sigh & 0x80000000); /* The default result for the case of two "equal" NaNs (signs may differ) is chosen to reproduce 80486 behaviour */ signalling = isNaN && !(a->sigh & 0x40000000); if (!signalling) { if (!isNaN) { /* pseudo-NaN, or other unsupported? */ if (control_word & CW_Invalid) { /* Masked response */ reg_copy(&CONST_QNaN, a); } EXCEPTION(EX_Invalid); return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special; } return TAG_Special; } if (control_word & CW_Invalid) { /* The masked response */ if (!(a->sigh & 0x80000000)) { /* pseudo-NaN ? */ reg_copy(&CONST_QNaN, a); } /* ensure a Quiet NaN */ a->sigh |= 0x40000000; } EXCEPTION(EX_Invalid); return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special; } /* Real operation attempted on two operands, one a NaN. */ /* Returns < 0 if the exception is unmasked */ int real_2op_NaN(FPU_REG const *b, u_char tagb, int deststnr, FPU_REG const *defaultNaN) { FPU_REG *dest = &st(deststnr); FPU_REG const *a = dest; u_char taga = FPU_gettagi(deststnr); FPU_REG const *x; int signalling, unsupported; if (taga == TAG_Special) taga = FPU_Special(a); if (tagb == TAG_Special) tagb = FPU_Special(b); /* TW_NaN is also used for unsupported data types. */ unsupported = ((taga == TW_NaN) && !((exponent(a) == EXP_OVER) && (a->sigh & 0x80000000))) || ((tagb == TW_NaN) && !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000))); if (unsupported) { if (control_word & CW_Invalid) { /* Masked response */ FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr); } EXCEPTION(EX_Invalid); return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special; } if (taga == TW_NaN) { x = a; if (tagb == TW_NaN) { signalling = !(a->sigh & b->sigh & 0x40000000); if (significand(b) > significand(a)) x = b; else if (significand(b) == significand(a)) { /* The default result for the case of two "equal" NaNs (signs may differ) is chosen to reproduce 80486 behaviour */ x = defaultNaN; } } else { /* return the quiet version of the NaN in a */ signalling = !(a->sigh & 0x40000000); } } else #ifdef PARANOID if (tagb == 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) || (control_word & CW_Invalid)) { if (!x) x = b; if (!(x->sigh & 0x80000000)) /* pseudo-NaN ? */ x = &CONST_QNaN; FPU_copy_to_regi(x, TAG_Special, deststnr); if (!signalling) return TAG_Special; /* ensure a Quiet NaN */ dest->sigh |= 0x40000000; } EXCEPTION(EX_Invalid); return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special; } /* Invalid arith operation on Valid registers */ /* Returns < 0 if the exception is unmasked */ asmlinkage int arith_invalid(int deststnr) { EXCEPTION(EX_Invalid); if (control_word & CW_Invalid) { /* The masked response */ FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr); } return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Valid; } /* Divide a finite number by zero */ asmlinkage int FPU_divide_by_zero(int deststnr, u_char sign) { FPU_REG *dest = &st(deststnr); int tag = TAG_Valid; if (control_word & CW_ZeroDiv) { /* The masked response */ FPU_copy_to_regi(&CONST_INF, TAG_Special, deststnr); setsign(dest, sign); tag = TAG_Special; } EXCEPTION(EX_ZeroDiv); return (!(control_word & CW_ZeroDiv) ? FPU_Exception : 0) | tag; } /* This may be called often, so keep it lean */ int set_precision_flag(int flags) { if (control_word & CW_Precision) { partial_status &= ~(SW_C1 & flags); partial_status |= flags; /* The masked response */ return 0; } else { EXCEPTION(flags); return 1; } } /* This may be called often, so keep it lean */ asmlinkage void set_precision_flag_up(void) { if (control_word & CW_Precision) partial_status |= (SW_Precision | SW_C1); /* The masked response */ else EXCEPTION(EX_Precision | SW_C1); } /* This may be called often, so keep it lean */ asmlinkage void set_precision_flag_down(void) { if (control_word & CW_Precision) { /* The masked response */ partial_status &= ~SW_C1; partial_status |= SW_Precision; } else EXCEPTION(EX_Precision); } asmlinkage int denormal_operand(void) { if (control_word & CW_Denormal) { /* The masked response */ partial_status |= SW_Denorm_Op; return TAG_Special; } else { EXCEPTION(EX_Denormal); return TAG_Special | FPU_Exception; } } asmlinkage int arith_overflow(FPU_REG *dest) { int tag = TAG_Valid; if (control_word & CW_Overflow) { /* The masked response */ /* ###### The response here depends upon the rounding mode */ reg_copy(&CONST_INF, dest); tag = TAG_Special; } else { /* Subtract the magic number from the exponent */ addexponent(dest, (-3 * (1 << 13))); } EXCEPTION(EX_Overflow); if (control_word & CW_Overflow) { /* The overflow exception is masked. */ /* By definition, precision is lost. The roundup bit (C1) is also set because we have "rounded" upwards to Infinity. */ EXCEPTION(EX_Precision | SW_C1); return tag; } return tag; } asmlinkage int arith_underflow(FPU_REG *dest) { int tag = TAG_Valid; if (control_word & CW_Underflow) { /* The masked response */ if (exponent16(dest) <= EXP_UNDER - 63) { reg_copy(&CONST_Z, dest); partial_status &= ~SW_C1; /* Round down. */ tag = TAG_Zero; } else { stdexp(dest); } } else { /* Add the magic number to the exponent. */ addexponent(dest, (3 * (1 << 13)) + EXTENDED_Ebias); } EXCEPTION(EX_Underflow); if (control_word & CW_Underflow) { /* The underflow exception is masked. */ EXCEPTION(EX_Precision); return tag; } return tag; } void FPU_stack_overflow(void) { if (control_word & CW_Invalid) { /* The masked response */ top--; FPU_copy_to_reg0(&CONST_QNaN, TAG_Special); } EXCEPTION(EX_StackOver); return; } void FPU_stack_underflow(void) { if (control_word & CW_Invalid) { /* The masked response */ FPU_copy_to_reg0(&CONST_QNaN, TAG_Special); } EXCEPTION(EX_StackUnder); return; } void FPU_stack_underflow_i(int i) { if (control_word & CW_Invalid) { /* The masked response */ FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i); } EXCEPTION(EX_StackUnder); return; } void FPU_stack_underflow_pop(int i) { if (control_word & CW_Invalid) { /* The masked response */ FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i); FPU_pop(); } EXCEPTION(EX_StackUnder); return; }