diff options
Diffstat (limited to 'kernel/arch/x86/math-emu/fpu_etc.c')
| -rw-r--r-- | kernel/arch/x86/math-emu/fpu_etc.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/kernel/arch/x86/math-emu/fpu_etc.c b/kernel/arch/x86/math-emu/fpu_etc.c new file mode 100644 index 000000000..233e5af56 --- /dev/null +++ b/kernel/arch/x86/math-emu/fpu_etc.c @@ -0,0 +1,130 @@ +/*---------------------------------------------------------------------------+ + | fpu_etc.c | + | | + | Implement a few FPU instructions. | + | | + | Copyright (C) 1992,1993,1994,1997 | + | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | + | Australia. E-mail billm@suburbia.net | + | | + | | + +---------------------------------------------------------------------------*/ + +#include "fpu_system.h" +#include "exception.h" +#include "fpu_emu.h" +#include "status_w.h" +#include "reg_constant.h" + +static void fchs(FPU_REG *st0_ptr, u_char st0tag) +{ + if (st0tag ^ TAG_Empty) { + signbyte(st0_ptr) ^= SIGN_NEG; + clear_C1(); + } else + FPU_stack_underflow(); +} + +static void fabs(FPU_REG *st0_ptr, u_char st0tag) +{ + if (st0tag ^ TAG_Empty) { + setpositive(st0_ptr); + clear_C1(); + } else + FPU_stack_underflow(); +} + +static void ftst_(FPU_REG *st0_ptr, u_char st0tag) +{ + switch (st0tag) { + case TAG_Zero: + setcc(SW_C3); + break; + case TAG_Valid: + if (getsign(st0_ptr) == SIGN_POS) + setcc(0); + else + setcc(SW_C0); + break; + case TAG_Special: + switch (FPU_Special(st0_ptr)) { + case TW_Denormal: + if (getsign(st0_ptr) == SIGN_POS) + setcc(0); + else + setcc(SW_C0); + if (denormal_operand() < 0) { +#ifdef PECULIAR_486 + /* This is weird! */ + if (getsign(st0_ptr) == SIGN_POS) + setcc(SW_C3); +#endif /* PECULIAR_486 */ + return; + } + break; + case TW_NaN: + setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */ + EXCEPTION(EX_Invalid); + break; + case TW_Infinity: + if (getsign(st0_ptr) == SIGN_POS) + setcc(0); + else + setcc(SW_C0); + break; + default: + setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */ + EXCEPTION(EX_INTERNAL | 0x14); + break; + } + break; + case TAG_Empty: + setcc(SW_C0 | SW_C2 | SW_C3); + EXCEPTION(EX_StackUnder); + break; + } +} + +static void fxam(FPU_REG *st0_ptr, u_char st0tag) +{ + int c = 0; + switch (st0tag) { + case TAG_Empty: + c = SW_C3 | SW_C0; + break; + case TAG_Zero: + c = SW_C3; + break; + case TAG_Valid: + c = SW_C2; + break; + case TAG_Special: + switch (FPU_Special(st0_ptr)) { + case TW_Denormal: + c = SW_C2 | SW_C3; /* Denormal */ + break; + case TW_NaN: + /* We also use NaN for unsupported types. */ + if ((st0_ptr->sigh & 0x80000000) + && (exponent(st0_ptr) == EXP_OVER)) + c = SW_C0; + break; + case TW_Infinity: + c = SW_C2 | SW_C0; + break; + } + } + if (getsign(st0_ptr) == SIGN_NEG) + c |= SW_C1; + setcc(c); +} + +static FUNC_ST0 const fp_etc_table[] = { + fchs, fabs, (FUNC_ST0) FPU_illegal, (FUNC_ST0) FPU_illegal, + ftst_, fxam, (FUNC_ST0) FPU_illegal, (FUNC_ST0) FPU_illegal +}; + +void FPU_etc(void) +{ + (fp_etc_table[FPU_rm]) (&st(0), FPU_gettag0()); +} |