diff options
Diffstat (limited to 'arch/i386/math-emu/fpu_entry.c')
| -rw-r--r-- | arch/i386/math-emu/fpu_entry.c | 760 |
1 files changed, 760 insertions, 0 deletions
diff --git a/arch/i386/math-emu/fpu_entry.c b/arch/i386/math-emu/fpu_entry.c new file mode 100644 index 000000000000..d93f16ef828f --- /dev/null +++ b/arch/i386/math-emu/fpu_entry.c @@ -0,0 +1,760 @@ +/*---------------------------------------------------------------------------+ + | fpu_entry.c | + | | + | The entry functions for wm-FPU-emu | + | | + | Copyright (C) 1992,1993,1994,1996,1997 | + | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | + | E-mail billm@suburbia.net | + | | + | See the files "README" and "COPYING" for further copyright and warranty | + | information. | + | | + +---------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------+ + | 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. | + +---------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------+ + | math_emulate(), restore_i387_soft() and save_i387_soft() are the only | + | entry points for wm-FPU-emu. | + +---------------------------------------------------------------------------*/ + +#include <linux/signal.h> +#include <linux/ptrace.h> + +#include <asm/uaccess.h> +#include <asm/desc.h> + +#include "fpu_system.h" +#include "fpu_emu.h" +#include "exception.h" +#include "control_w.h" +#include "status_w.h" + +#define __BAD__ FPU_illegal /* Illegal on an 80486, causes SIGILL */ + +#ifndef NO_UNDOC_CODE /* Un-documented FPU op-codes supported by default. */ + +/* WARNING: These codes are not documented by Intel in their 80486 manual + and may not work on FPU clones or later Intel FPUs. */ + +/* Changes to support the un-doc codes provided by Linus Torvalds. */ + +#define _d9_d8_ fstp_i /* unofficial code (19) */ +#define _dc_d0_ fcom_st /* unofficial code (14) */ +#define _dc_d8_ fcompst /* unofficial code (1c) */ +#define _dd_c8_ fxch_i /* unofficial code (0d) */ +#define _de_d0_ fcompst /* unofficial code (16) */ +#define _df_c0_ ffreep /* unofficial code (07) ffree + pop */ +#define _df_c8_ fxch_i /* unofficial code (0f) */ +#define _df_d0_ fstp_i /* unofficial code (17) */ +#define _df_d8_ fstp_i /* unofficial code (1f) */ + +static FUNC const st_instr_table[64] = { + fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, _df_c0_, + fmul__, fxch_i, __BAD__, __BAD__, fmul_i, _dd_c8_, fmulp_, _df_c8_, + fcom_st, fp_nop, __BAD__, __BAD__, _dc_d0_, fst_i_, _de_d0_, _df_d0_, + fcompst, _d9_d8_, __BAD__, __BAD__, _dc_d8_, fstp_i, fcompp, _df_d8_, + fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_, + fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__, + fdiv__, FPU_triga, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__, + fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__, +}; + +#else /* Support only documented FPU op-codes */ + +static FUNC const st_instr_table[64] = { + fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, __BAD__, + fmul__, fxch_i, __BAD__, __BAD__, fmul_i, __BAD__, fmulp_, __BAD__, + fcom_st, fp_nop, __BAD__, __BAD__, __BAD__, fst_i_, __BAD__, __BAD__, + fcompst, __BAD__, __BAD__, __BAD__, __BAD__, fstp_i, fcompp, __BAD__, + fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_, + fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__, + fdiv__, FPU_triga, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__, + fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__, +}; + +#endif /* NO_UNDOC_CODE */ + + +#define _NONE_ 0 /* Take no special action */ +#define _REG0_ 1 /* Need to check for not empty st(0) */ +#define _REGI_ 2 /* Need to check for not empty st(0) and st(rm) */ +#define _REGi_ 0 /* Uses st(rm) */ +#define _PUSH_ 3 /* Need to check for space to push onto stack */ +#define _null_ 4 /* Function illegal or not implemented */ +#define _REGIi 5 /* Uses st(0) and st(rm), result to st(rm) */ +#define _REGIp 6 /* Uses st(0) and st(rm), result to st(rm) then pop */ +#define _REGIc 0 /* Compare st(0) and st(rm) */ +#define _REGIn 0 /* Uses st(0) and st(rm), but handle checks later */ + +#ifndef NO_UNDOC_CODE + +/* Un-documented FPU op-codes supported by default. (see above) */ + +static u_char const type_table[64] = { + _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_, + _REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_, + _REGIc, _NONE_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_, + _REGIc, _REG0_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_, + _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_, + _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_, + _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_, + _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_ +}; + +#else /* Support only documented FPU op-codes */ + +static u_char const type_table[64] = { + _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _null_, + _REGI_, _REGIn, _null_, _null_, _REGIi, _null_, _REGIp, _null_, + _REGIc, _NONE_, _null_, _null_, _null_, _REG0_, _null_, _null_, + _REGIc, _null_, _null_, _null_, _null_, _REG0_, _REGIc, _null_, + _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_, + _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_, + _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_, + _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_ +}; + +#endif /* NO_UNDOC_CODE */ + + +#ifdef RE_ENTRANT_CHECKING +u_char emulating=0; +#endif /* RE_ENTRANT_CHECKING */ + +static int valid_prefix(u_char *Byte, u_char __user **fpu_eip, + overrides *override); + +asmlinkage void math_emulate(long arg) +{ + u_char FPU_modrm, byte1; + unsigned short code; + fpu_addr_modes addr_modes; + int unmasked; + FPU_REG loaded_data; + FPU_REG *st0_ptr; + u_char loaded_tag, st0_tag; + void __user *data_address; + struct address data_sel_off; + struct address entry_sel_off; + unsigned long code_base = 0; + unsigned long code_limit = 0; /* Initialized to stop compiler warnings */ + struct desc_struct code_descriptor; + +#ifdef RE_ENTRANT_CHECKING + if ( emulating ) + { + printk("ERROR: wm-FPU-emu is not RE-ENTRANT!\n"); + } + RE_ENTRANT_CHECK_ON; +#endif /* RE_ENTRANT_CHECKING */ + + if (!used_math()) + { + finit(); + set_used_math(); + } + + SETUP_DATA_AREA(arg); + + FPU_ORIG_EIP = FPU_EIP; + + if ( (FPU_EFLAGS & 0x00020000) != 0 ) + { + /* Virtual 8086 mode */ + addr_modes.default_mode = VM86; + FPU_EIP += code_base = FPU_CS << 4; + code_limit = code_base + 0xffff; /* Assumes code_base <= 0xffff0000 */ + } + else if ( FPU_CS == __USER_CS && FPU_DS == __USER_DS ) + { + addr_modes.default_mode = 0; + } + else if ( FPU_CS == __KERNEL_CS ) + { + printk("math_emulate: %04x:%08lx\n",FPU_CS,FPU_EIP); + panic("Math emulation needed in kernel"); + } + else + { + + if ( (FPU_CS & 4) != 4 ) /* Must be in the LDT */ + { + /* Can only handle segmented addressing via the LDT + for now, and it must be 16 bit */ + printk("FPU emulator: Unsupported addressing mode\n"); + math_abort(FPU_info, SIGILL); + } + + code_descriptor = LDT_DESCRIPTOR(FPU_CS); + if ( SEG_D_SIZE(code_descriptor) ) + { + /* The above test may be wrong, the book is not clear */ + /* Segmented 32 bit protected mode */ + addr_modes.default_mode = SEG32; + } + else + { + /* 16 bit protected mode */ + addr_modes.default_mode = PM16; + } + FPU_EIP += code_base = SEG_BASE_ADDR(code_descriptor); + code_limit = code_base + + (SEG_LIMIT(code_descriptor)+1) * SEG_GRANULARITY(code_descriptor) + - 1; + if ( code_limit < code_base ) code_limit = 0xffffffff; + } + + FPU_lookahead = 1; + if (current->ptrace & PT_PTRACED) + FPU_lookahead = 0; + + if ( !valid_prefix(&byte1, (u_char __user **)&FPU_EIP, + &addr_modes.override) ) + { + RE_ENTRANT_CHECK_OFF; + printk("FPU emulator: Unknown prefix byte 0x%02x, probably due to\n" + "FPU emulator: self-modifying code! (emulation impossible)\n", + byte1); + RE_ENTRANT_CHECK_ON; + EXCEPTION(EX_INTERNAL|0x126); + math_abort(FPU_info,SIGILL); + } + +do_another_FPU_instruction: + + no_ip_update = 0; + + FPU_EIP++; /* We have fetched the prefix and first code bytes. */ + + if ( addr_modes.default_mode ) + { + /* This checks for the minimum instruction bytes. + We also need to check any extra (address mode) code access. */ + if ( FPU_EIP > code_limit ) + math_abort(FPU_info,SIGSEGV); + } + + if ( (byte1 & 0xf8) != 0xd8 ) + { + if ( byte1 == FWAIT_OPCODE ) + { + if (partial_status & SW_Summary) + goto do_the_FPU_interrupt; + else + goto FPU_fwait_done; + } +#ifdef PARANOID + EXCEPTION(EX_INTERNAL|0x128); + math_abort(FPU_info,SIGILL); +#endif /* PARANOID */ + } + + RE_ENTRANT_CHECK_OFF; + FPU_code_access_ok(1); + FPU_get_user(FPU_modrm, (u_char __user *) FPU_EIP); + RE_ENTRANT_CHECK_ON; + FPU_EIP++; + + if (partial_status & SW_Summary) + { + /* Ignore the error for now if the current instruction is a no-wait + control instruction */ + /* The 80486 manual contradicts itself on this topic, + but a real 80486 uses the following instructions: + fninit, fnstenv, fnsave, fnstsw, fnstenv, fnclex. + */ + code = (FPU_modrm << 8) | byte1; + if ( ! ( (((code & 0xf803) == 0xe003) || /* fnclex, fninit, fnstsw */ + (((code & 0x3003) == 0x3001) && /* fnsave, fnstcw, fnstenv, + fnstsw */ + ((code & 0xc000) != 0xc000))) ) ) + { + /* + * We need to simulate the action of the kernel to FPU + * interrupts here. + */ + do_the_FPU_interrupt: + + FPU_EIP = FPU_ORIG_EIP; /* Point to current FPU instruction. */ + + RE_ENTRANT_CHECK_OFF; + current->thread.trap_no = 16; + current->thread.error_code = 0; + send_sig(SIGFPE, current, 1); + return; + } + } + + entry_sel_off.offset = FPU_ORIG_EIP; + entry_sel_off.selector = FPU_CS; + entry_sel_off.opcode = (byte1 << 8) | FPU_modrm; + + FPU_rm = FPU_modrm & 7; + + if ( FPU_modrm < 0300 ) + { + /* All of these instructions use the mod/rm byte to get a data address */ + + if ( (addr_modes.default_mode & SIXTEEN) + ^ (addr_modes.override.address_size == ADDR_SIZE_PREFIX) ) + data_address = FPU_get_address_16(FPU_modrm, &FPU_EIP, &data_sel_off, + addr_modes); + else + data_address = FPU_get_address(FPU_modrm, &FPU_EIP, &data_sel_off, + addr_modes); + + if ( addr_modes.default_mode ) + { + if ( FPU_EIP-1 > code_limit ) + math_abort(FPU_info,SIGSEGV); + } + + if ( !(byte1 & 1) ) + { + unsigned short status1 = partial_status; + + st0_ptr = &st(0); + st0_tag = FPU_gettag0(); + + /* Stack underflow has priority */ + if ( NOT_EMPTY_ST0 ) + { + if ( addr_modes.default_mode & PROTECTED ) + { + /* This table works for 16 and 32 bit protected mode */ + if ( access_limit < data_sizes_16[(byte1 >> 1) & 3] ) + math_abort(FPU_info,SIGSEGV); + } + + unmasked = 0; /* Do this here to stop compiler warnings. */ + switch ( (byte1 >> 1) & 3 ) + { + case 0: + unmasked = FPU_load_single((float __user *)data_address, + &loaded_data); + loaded_tag = unmasked & 0xff; + unmasked &= ~0xff; + break; + case 1: + loaded_tag = FPU_load_int32((long __user *)data_address, &loaded_data); + break; + case 2: + unmasked = FPU_load_double((double __user *)data_address, + &loaded_data); + loaded_tag = unmasked & 0xff; + unmasked &= ~0xff; + break; + case 3: + default: /* Used here to suppress gcc warnings. */ + loaded_tag = FPU_load_int16((short __user *)data_address, &loaded_data); + break; + } + + /* No more access to user memory, it is safe + to use static data now */ + + /* NaN operands have the next priority. */ + /* We have to delay looking at st(0) until after + loading the data, because that data might contain an SNaN */ + if ( ((st0_tag == TAG_Special) && isNaN(st0_ptr)) || + ((loaded_tag == TAG_Special) && isNaN(&loaded_data)) ) + { + /* Restore the status word; we might have loaded a + denormal. */ + partial_status = status1; + if ( (FPU_modrm & 0x30) == 0x10 ) + { + /* fcom or fcomp */ + EXCEPTION(EX_Invalid); + setcc(SW_C3 | SW_C2 | SW_C0); + if ( (FPU_modrm & 0x08) && (control_word & CW_Invalid) ) + FPU_pop(); /* fcomp, masked, so we pop. */ + } + else + { + if ( loaded_tag == TAG_Special ) + loaded_tag = FPU_Special(&loaded_data); +#ifdef PECULIAR_486 + /* This is not really needed, but gives behaviour + identical to an 80486 */ + if ( (FPU_modrm & 0x28) == 0x20 ) + /* fdiv or fsub */ + real_2op_NaN(&loaded_data, loaded_tag, 0, &loaded_data); + else +#endif /* PECULIAR_486 */ + /* fadd, fdivr, fmul, or fsubr */ + real_2op_NaN(&loaded_data, loaded_tag, 0, st0_ptr); + } + goto reg_mem_instr_done; + } + + if ( unmasked && !((FPU_modrm & 0x30) == 0x10) ) + { + /* Is not a comparison instruction. */ + if ( (FPU_modrm & 0x38) == 0x38 ) + { + /* fdivr */ + if ( (st0_tag == TAG_Zero) && + ((loaded_tag == TAG_Valid) + || (loaded_tag == TAG_Special + && isdenormal(&loaded_data))) ) + { + if ( FPU_divide_by_zero(0, getsign(&loaded_data)) + < 0 ) + { + /* We use the fact here that the unmasked + exception in the loaded data was for a + denormal operand */ + /* Restore the state of the denormal op bit */ + partial_status &= ~SW_Denorm_Op; + partial_status |= status1 & SW_Denorm_Op; + } + else + setsign(st0_ptr, getsign(&loaded_data)); + } + } + goto reg_mem_instr_done; + } + + switch ( (FPU_modrm >> 3) & 7 ) + { + case 0: /* fadd */ + clear_C1(); + FPU_add(&loaded_data, loaded_tag, 0, control_word); + break; + case 1: /* fmul */ + clear_C1(); + FPU_mul(&loaded_data, loaded_tag, 0, control_word); + break; + case 2: /* fcom */ + FPU_compare_st_data(&loaded_data, loaded_tag); + break; + case 3: /* fcomp */ + if ( !FPU_compare_st_data(&loaded_data, loaded_tag) + && !unmasked ) + FPU_pop(); + break; + case 4: /* fsub */ + clear_C1(); + FPU_sub(LOADED|loaded_tag, (int)&loaded_data, control_word); + break; + case 5: /* fsubr */ + clear_C1(); + FPU_sub(REV|LOADED|loaded_tag, (int)&loaded_data, control_word); + break; + case 6: /* fdiv */ + clear_C1(); + FPU_div(LOADED|loaded_tag, (int)&loaded_data, control_word); + break; + case 7: /* fdivr */ + clear_C1(); + if ( st0_tag == TAG_Zero ) + partial_status = status1; /* Undo any denorm tag, + zero-divide has priority. */ + FPU_div(REV|LOADED|loaded_tag, (int)&loaded_data, control_word); + break; + } + } + else + { + if ( (FPU_modrm & 0x30) == 0x10 ) + { + /* The instruction is fcom or fcomp */ + EXCEPTION(EX_StackUnder); + setcc(SW_C3 | SW_C2 | SW_C0); + if ( (FPU_modrm & 0x08) && (control_word & CW_Invalid) ) + FPU_pop(); /* fcomp */ + } + else + FPU_stack_underflow(); + } + reg_mem_instr_done: + operand_address = data_sel_off; + } + else + { + if ( !(no_ip_update = + FPU_load_store(((FPU_modrm & 0x38) | (byte1 & 6)) >> 1, + addr_modes, data_address)) ) + { + operand_address = data_sel_off; + } + } + + } + else + { + /* None of these instructions access user memory */ + u_char instr_index = (FPU_modrm & 0x38) | (byte1 & 7); + +#ifdef PECULIAR_486 + /* This is supposed to be undefined, but a real 80486 seems + to do this: */ + operand_address.offset = 0; + operand_address.selector = FPU_DS; +#endif /* PECULIAR_486 */ + + st0_ptr = &st(0); + st0_tag = FPU_gettag0(); + switch ( type_table[(int) instr_index] ) + { + case _NONE_: /* also _REGIc: _REGIn */ + break; + case _REG0_: + if ( !NOT_EMPTY_ST0 ) + { + FPU_stack_underflow(); + goto FPU_instruction_done; + } + break; + case _REGIi: + if ( !NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm) ) + { + FPU_stack_underflow_i(FPU_rm); + goto FPU_instruction_done; + } + break; + case _REGIp: + if ( !NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm) ) + { + FPU_stack_underflow_pop(FPU_rm); + goto FPU_instruction_done; + } + break; + case _REGI_: + if ( !NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm) ) + { + FPU_stack_underflow(); + goto FPU_instruction_done; + } + break; + case _PUSH_: /* Only used by the fld st(i) instruction */ + break; + case _null_: + FPU_illegal(); + goto FPU_instruction_done; + default: + EXCEPTION(EX_INTERNAL|0x111); + goto FPU_instruction_done; + } + (*st_instr_table[(int) instr_index])(); + +FPU_instruction_done: + ; + } + + if ( ! no_ip_update ) + instruction_address = entry_sel_off; + +FPU_fwait_done: + +#ifdef DEBUG + RE_ENTRANT_CHECK_OFF; + FPU_printall(); + RE_ENTRANT_CHECK_ON; +#endif /* DEBUG */ + + if (FPU_lookahead && !need_resched()) + { + FPU_ORIG_EIP = FPU_EIP - code_base; + if ( valid_prefix(&byte1, (u_char __user **)&FPU_EIP, + &addr_modes.override) ) + goto do_another_FPU_instruction; + } + + if ( addr_modes.default_mode ) + FPU_EIP -= code_base; + + RE_ENTRANT_CHECK_OFF; +} + + +/* Support for prefix bytes is not yet complete. To properly handle + all prefix bytes, further changes are needed in the emulator code + which accesses user address space. Access to separate segments is + important for msdos emulation. */ +static int valid_prefix(u_char *Byte, u_char __user **fpu_eip, + overrides *override) +{ + u_char byte; + u_char __user *ip = *fpu_eip; + + *override = (overrides) { 0, 0, PREFIX_DEFAULT }; /* defaults */ + + RE_ENTRANT_CHECK_OFF; + FPU_code_access_ok(1); + FPU_get_user(byte, ip); + RE_ENTRANT_CHECK_ON; + + while ( 1 ) + { + switch ( byte ) + { + case ADDR_SIZE_PREFIX: + override->address_size = ADDR_SIZE_PREFIX; + goto do_next_byte; + + case OP_SIZE_PREFIX: + override->operand_size = OP_SIZE_PREFIX; + goto do_next_byte; + + case PREFIX_CS: + override->segment = PREFIX_CS_; + goto do_next_byte; + case PREFIX_ES: + override->segment = PREFIX_ES_; + goto do_next_byte; + case PREFIX_SS: + override->segment = PREFIX_SS_; + goto do_next_byte; + case PREFIX_FS: + override->segment = PREFIX_FS_; + goto do_next_byte; + case PREFIX_GS: + override->segment = PREFIX_GS_; + goto do_next_byte; + case PREFIX_DS: + override->segment = PREFIX_DS_; + goto do_next_byte; + +/* lock is not a valid prefix for FPU instructions, + let the cpu handle it to generate a SIGILL. */ +/* case PREFIX_LOCK: */ + + /* rep.. prefixes have no meaning for FPU instructions */ + case PREFIX_REPE: + case PREFIX_REPNE: + + do_next_byte: + ip++; + RE_ENTRANT_CHECK_OFF; + FPU_code_access_ok(1); + FPU_get_user(byte, ip); + RE_ENTRANT_CHECK_ON; + break; + case FWAIT_OPCODE: + *Byte = byte; + return 1; + default: + if ( (byte & 0xf8) == 0xd8 ) + { + *Byte = byte; + *fpu_eip = ip; + return 1; + } + else + { + /* Not a valid sequence of prefix bytes followed by + an FPU instruction. */ + *Byte = byte; /* Needed for error message. */ + return 0; + } + } + } +} + + +void math_abort(struct info * info, unsigned int signal) +{ + FPU_EIP = FPU_ORIG_EIP; + current->thread.trap_no = 16; + current->thread.error_code = 0; + send_sig(signal,current,1); + RE_ENTRANT_CHECK_OFF; + __asm__("movl %0,%%esp ; ret": :"g" (((long) info)-4)); +#ifdef PARANOID + printk("ERROR: wm-FPU-emu math_abort failed!\n"); +#endif /* PARANOID */ +} + + + +#define S387 ((struct i387_soft_struct *)s387) +#define sstatus_word() \ + ((S387->swd & ~SW_Top & 0xffff) | ((S387->ftop << SW_Top_Shift) & SW_Top)) + +int restore_i387_soft(void *s387, struct _fpstate __user *buf) +{ + u_char __user *d = (u_char __user *)buf; + int offset, other, i, tags, regnr, tag, newtop; + + RE_ENTRANT_CHECK_OFF; + FPU_access_ok(VERIFY_READ, d, 7*4 + 8*10); + if (__copy_from_user(&S387->cwd, d, 7*4)) + return -1; + RE_ENTRANT_CHECK_ON; + + d += 7*4; + + S387->ftop = (S387->swd >> SW_Top_Shift) & 7; + offset = (S387->ftop & 7) * 10; + other = 80 - offset; + + RE_ENTRANT_CHECK_OFF; + /* Copy all registers in stack order. */ + if (__copy_from_user(((u_char *)&S387->st_space)+offset, d, other)) + return -1; + if ( offset ) + if (__copy_from_user((u_char *)&S387->st_space, d+other, offset)) + return -1; + RE_ENTRANT_CHECK_ON; + + /* The tags may need to be corrected now. */ + tags = S387->twd; + newtop = S387->ftop; + for ( i = 0; i < 8; i++ ) + { + regnr = (i+newtop) & 7; + if ( ((tags >> ((regnr & 7)*2)) & 3) != TAG_Empty ) + { + /* The loaded data over-rides all other cases. */ + tag = FPU_tagof((FPU_REG *)((u_char *)S387->st_space + 10*regnr)); + tags &= ~(3 << (regnr*2)); + tags |= (tag & 3) << (regnr*2); + } + } + S387->twd = tags; + + return 0; +} + + +int save_i387_soft(void *s387, struct _fpstate __user * buf) +{ + u_char __user *d = (u_char __user *)buf; + int offset = (S387->ftop & 7) * 10, other = 80 - offset; + + RE_ENTRANT_CHECK_OFF; + FPU_access_ok(VERIFY_WRITE, d, 7*4 + 8*10); +#ifdef PECULIAR_486 + S387->cwd &= ~0xe080; + /* An 80486 sets nearly all of the reserved bits to 1. */ + S387->cwd |= 0xffff0040; + S387->swd = sstatus_word() | 0xffff0000; + S387->twd |= 0xffff0000; + S387->fcs &= ~0xf8000000; + S387->fos |= 0xffff0000; +#endif /* PECULIAR_486 */ + __copy_to_user(d, &S387->cwd, 7*4); + RE_ENTRANT_CHECK_ON; + + d += 7*4; + + RE_ENTRANT_CHECK_OFF; + /* Copy all registers in stack order. */ + if (__copy_to_user(d, ((u_char *)&S387->st_space)+offset, other)) + return -1; + if ( offset ) + if (__copy_to_user(d+other, (u_char *)&S387->st_space, offset)) + return -1 + RE_ENTRANT_CHECK_ON; + + return 1; +} |
