Dear all, I encountered one problem about "executing self-defined 32bit shift-left routine too long"...
That is, I built my own routine to execute 32-bit shift left operation and found it takes too long(Due to some reason 32bit shift left is NOT allowed in my project currently...)
[code body]
UINT32 ShiftLeft32Bits(UINT32 Operand, UINT8 ShiftValue){ bit Carry; OperandDW = Operand; while(ShiftValue>0){ Carry=0; if(OperandDWLo&0x8000) Carry=1; OperandDWLo<<=1; OperandDWHi = (OperandDWHi<<1) | Carry; ShiftValue-=1; } return OperandDW; }
[Statistics] if "Operand = ShiftLeft32Bits(x1, 31);" => cost 60us ( where Operand,x1 are 4-byte xdata variables)
My question is: is it possible to "optimize" above code segments(favor speed) ? Thanks in advance...
p.s I am implementing sha256 calculation...