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Diffstat (limited to 'arch/x86/math-emu/errors.c')
| -rw-r--r-- | arch/x86/math-emu/errors.c | 685 |
1 files changed, 685 insertions, 0 deletions
diff --git a/arch/x86/math-emu/errors.c b/arch/x86/math-emu/errors.c new file mode 100644 index 000000000..6b468517a --- /dev/null +++ b/arch/x86/math-emu/errors.c @@ -0,0 +1,685 @@ +// SPDX-License-Identifier: GPL-2.0 +/*---------------------------------------------------------------------------+ + | 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 <linux/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 __visible 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)) { + /* 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 __visible 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 __visible 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 __visible 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 __visible 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 __visible 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 __visible 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 __visible 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; + +} |