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...
And just think what it could do it in if you had written in assembler!
Hmmmm.... that does very much rely on the skill of the particular assembly programmer...