diff options
Diffstat (limited to 'arch/x86/math-emu/reg_mul.c')
| -rw-r--r-- | arch/x86/math-emu/reg_mul.c | 163 |
1 files changed, 73 insertions, 90 deletions
diff --git a/arch/x86/math-emu/reg_mul.c b/arch/x86/math-emu/reg_mul.c index 40f50b61bc67..36c37f71f713 100644 --- a/arch/x86/math-emu/reg_mul.c +++ b/arch/x86/math-emu/reg_mul.c @@ -20,7 +20,6 @@ #include "reg_constant.h" #include "fpu_system.h" - /* Multiply two registers to give a register result. The sources are st(deststnr) and (b,tagb,signb). @@ -29,104 +28,88 @@ /* This routine must be called with non-empty source registers */ int FPU_mul(FPU_REG const *b, u_char tagb, int deststnr, int control_w) { - FPU_REG *a = &st(deststnr); - FPU_REG *dest = a; - u_char taga = FPU_gettagi(deststnr); - u_char saved_sign = getsign(dest); - u_char sign = (getsign(a) ^ getsign(b)); - int tag; - + FPU_REG *a = &st(deststnr); + FPU_REG *dest = a; + u_char taga = FPU_gettagi(deststnr); + u_char saved_sign = getsign(dest); + u_char sign = (getsign(a) ^ getsign(b)); + int tag; - if ( !(taga | tagb) ) - { - /* Both regs Valid, this should be the most common case. */ + if (!(taga | tagb)) { + /* Both regs Valid, this should be the most common case. */ - tag = FPU_u_mul(a, b, dest, control_w, sign, exponent(a) + exponent(b)); - if ( tag < 0 ) - { - setsign(dest, saved_sign); - return tag; + tag = + FPU_u_mul(a, b, dest, control_w, sign, + exponent(a) + exponent(b)); + if (tag < 0) { + setsign(dest, saved_sign); + return tag; + } + FPU_settagi(deststnr, tag); + return tag; } - FPU_settagi(deststnr, tag); - return tag; - } - if ( taga == TAG_Special ) - taga = FPU_Special(a); - if ( tagb == TAG_Special ) - tagb = FPU_Special(b); + if (taga == TAG_Special) + taga = FPU_Special(a); + if (tagb == TAG_Special) + tagb = FPU_Special(b); - if ( ((taga == TAG_Valid) && (tagb == TW_Denormal)) + if (((taga == TAG_Valid) && (tagb == TW_Denormal)) || ((taga == TW_Denormal) && (tagb == TAG_Valid)) - || ((taga == TW_Denormal) && (tagb == TW_Denormal)) ) - { - FPU_REG x, y; - if ( denormal_operand() < 0 ) - return FPU_Exception; - - FPU_to_exp16(a, &x); - FPU_to_exp16(b, &y); - tag = FPU_u_mul(&x, &y, dest, control_w, sign, - exponent16(&x) + exponent16(&y)); - if ( tag < 0 ) - { - setsign(dest, saved_sign); - return tag; - } - FPU_settagi(deststnr, tag); - return tag; - } - else if ( (taga <= TW_Denormal) && (tagb <= TW_Denormal) ) - { - if ( ((tagb == TW_Denormal) || (taga == TW_Denormal)) - && (denormal_operand() < 0) ) - return FPU_Exception; + || ((taga == TW_Denormal) && (tagb == TW_Denormal))) { + FPU_REG x, y; + if (denormal_operand() < 0) + return FPU_Exception; - /* Must have either both arguments == zero, or - one valid and the other zero. - The result is therefore zero. */ - FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); - /* The 80486 book says that the answer is +0, but a real - 80486 behaves this way. - IEEE-754 apparently says it should be this way. */ - setsign(dest, sign); - return TAG_Zero; - } - /* Must have infinities, NaNs, etc */ - else if ( (taga == TW_NaN) || (tagb == TW_NaN) ) - { - return real_2op_NaN(b, tagb, deststnr, &st(0)); - } - else if ( ((taga == TW_Infinity) && (tagb == TAG_Zero)) - || ((tagb == TW_Infinity) && (taga == TAG_Zero)) ) - { - return arith_invalid(deststnr); /* Zero*Infinity is invalid */ - } - else if ( ((taga == TW_Denormal) || (tagb == TW_Denormal)) - && (denormal_operand() < 0) ) - { - return FPU_Exception; - } - else if (taga == TW_Infinity) - { - FPU_copy_to_regi(a, TAG_Special, deststnr); - setsign(dest, sign); - return TAG_Special; - } - else if (tagb == TW_Infinity) - { - FPU_copy_to_regi(b, TAG_Special, deststnr); - setsign(dest, sign); - return TAG_Special; - } + FPU_to_exp16(a, &x); + FPU_to_exp16(b, &y); + tag = FPU_u_mul(&x, &y, dest, control_w, sign, + exponent16(&x) + exponent16(&y)); + if (tag < 0) { + setsign(dest, saved_sign); + return tag; + } + FPU_settagi(deststnr, tag); + return tag; + } else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) { + if (((tagb == TW_Denormal) || (taga == TW_Denormal)) + && (denormal_operand() < 0)) + return FPU_Exception; + /* Must have either both arguments == zero, or + one valid and the other zero. + The result is therefore zero. */ + FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); + /* The 80486 book says that the answer is +0, but a real + 80486 behaves this way. + IEEE-754 apparently says it should be this way. */ + setsign(dest, sign); + return TAG_Zero; + } + /* Must have infinities, NaNs, etc */ + else if ((taga == TW_NaN) || (tagb == TW_NaN)) { + return real_2op_NaN(b, tagb, deststnr, &st(0)); + } else if (((taga == TW_Infinity) && (tagb == TAG_Zero)) + || ((tagb == TW_Infinity) && (taga == TAG_Zero))) { + return arith_invalid(deststnr); /* Zero*Infinity is invalid */ + } else if (((taga == TW_Denormal) || (tagb == TW_Denormal)) + && (denormal_operand() < 0)) { + return FPU_Exception; + } else if (taga == TW_Infinity) { + FPU_copy_to_regi(a, TAG_Special, deststnr); + setsign(dest, sign); + return TAG_Special; + } else if (tagb == TW_Infinity) { + FPU_copy_to_regi(b, TAG_Special, deststnr); + setsign(dest, sign); + return TAG_Special; + } #ifdef PARANOID - else - { - EXCEPTION(EX_INTERNAL|0x102); - return FPU_Exception; - } -#endif /* PARANOID */ + else { + EXCEPTION(EX_INTERNAL | 0x102); + return FPU_Exception; + } +#endif /* PARANOID */ return 0; } |
