| 111,16 → 111,128 |
|---|
| //rounding - if first bit after mantisa is set then round up |
| mant1+=0x20; |
| |
| if (mant1&0x40000000) { |
| ++exp1; |
| mant1>>=1; |
| }; |
| |
| a.parts.exp=exp1; |
| a.parts.mantisa=mant1>>6; |
| a.parts.mantisa = ((mant1&(~0x20000000))>>6); /*Clear hidden bit and shift */ |
| return a; |
| }; |
| |
| /** Substract two float32 numbers with same signs |
| /** Subtract two float32 numbers with same signs |
| */ |
| float32 subFloat32(float32 a, float32 b) |
| { |
| int expdiff; |
| __u32 exp1,exp2,mant1,mant2; |
| float32 result; |
| |
| result.f = 0; |
| |
| expdiff=a.parts.exp - b.parts.exp; |
| if ((expdiff<0)||((expdiff==0)&&(a.parts.mantisa<b.parts.mantisa))) { |
| if (isFloat32NaN(b)) { |
| //TODO: fix SigNaN |
| if (isFloat32SigNaN(b)) { |
| }; |
| return b; |
| }; |
| |
| if (b.parts.exp==0xFF) { |
| b.parts.sign=!b.parts.sign; /* num -(+-inf) = -+inf */ |
| return b; |
| } |
| |
| result.parts.sign = !a.parts.sign; |
| |
| mant1=b.parts.mantisa; |
| exp1=b.parts.exp; |
| mant2=a.parts.mantisa; |
| exp2=a.parts.exp; |
| expdiff*=-1; |
| } else { |
| if (isFloat32NaN(a)) { |
| //TODO: fix SigNaN |
| if ((isFloat32SigNaN(a))||(isFloat32SigNaN(b))) { |
| }; |
| return a; |
| }; |
| |
| if (a.parts.exp==0xFF) { |
| if (b.parts.exp==0xFF) { |
| /* inf - inf => nan */ |
| //TODO: fix exception |
| result.binary = FLOAT32_NAN; |
| return result; |
| }; |
| return a; |
| } |
| |
| result.parts.sign = a.parts.sign; |
| |
| mant1=a.parts.mantisa; |
| exp1=a.parts.exp; |
| mant2=b.parts.mantisa; |
| exp2=b.parts.exp; |
| |
| |
| |
| }; |
| |
| if (exp1==0) { |
| //both are denormalized |
| result.parts.mantisa=mant1-mant2; |
| if (result.parts.mantisa>mant1) { |
| //TODO: underflow exception |
| return result; |
| }; |
| result.parts.exp=0; |
| return result; |
| }; |
| |
| // create some space for rounding |
| mant1<<=6; |
| mant2<<=6; |
| |
| mant1|=0x20000000; //add hidden bit |
| |
| |
| if (exp2==0) { |
| --expdiff; |
| } else { |
| mant2|=0x20000000; //hidden bit |
| }; |
| |
| if (expdiff>24) { |
| goto done; |
| }; |
| |
| mant1 = mant1-(mant2>>expdiff); |
| done: |
| |
| //TODO: find first nonzero digit and shift result and detect possibly underflow |
| while ((exp1>0)&&(!(mant1&0x20000000))) { |
| exp1--; |
| mant1 <<= 1; |
| if(mant1 == 0) { |
| /* Realy is it an underflow? ... */ |
| //TODO: fix underflow |
| }; |
| }; |
| |
| //rounding - if first bit after mantisa is set then round up |
| mant1 += 0x20; |
| |
| if (mant1&0x40000000) { |
| ++exp1; |
| mant1>>=1; |
| }; |
| |
| result.parts.mantisa = ((mant1&(~0x20000000))>>6); /*Clear hidden bit and shift */ |
| result.parts.exp = exp1; |
| |
| return result; |
| }; |
| |