Extended Precision Operations Little Endian vs Big Endian Which is ...

C codeint i,j;i = i + j;LSByte addditionif C=1, add 1 toMSByteMSByte adddition16-bit AdditionPIC16 assemblyCBLOCK 0x040i:2,j:2ENDC;; i = i + jmovf j,w ; w ← j (LSB)addwf i,f ;i LSB ← w + i LSBbtfsc STATUS, Cincf i+1,f ;i MSB ← i MSB + 1movf j+1,w ; w ← j (MSB)addwf i+1,f ; i MSB← w +i MSB16-bit Subtraction using Carry Flag0x 34 10- 0x 22 400x 11 D0- ~C flagSubtract two LSBytes,if Cflag =0 after subtraction (a borrow), then decrement (-1)MSByte before MSByte subtractionV 0.1 7V 0.1 8C codeint i,j;i = i - j;LSByte subtractionif C=0, subtract 1from MSByteMSByte subtraction16-bit SubtractionPIC16 assemblyCBLOCK 0x040i:2,j:2ENDC;; i = i - jmovf j,w ; w ← j (LSB)subwf i,f ;i LSB ← i LSB - wbtfss STATUS, Cdecf i+1,f ;i MSB ← i MSB - 1movf j+1,w ; w ← j (MSB)subwf i+1,f ; i MSB← i MSB - wV 0.1 9addwfc f, dsubwfb f, dPIC16 assemblyPIC18 Add/Sub with Carrymovf j,w ; w ←j(LSB)addwf i,f ;LSB additionbtfsc STATUS, Cincf i+1,f ;MSB+1movf j+1,w ; w← j (MSB)addwf i+1,f ;MSB addition; d ← d + f + Cflag (add with carry); d ← f - d - ~Cflag (subtract with borrow)int i,j;i = i + j;PIC18 assemblymovf j,w ; w ←j(LSB)addwf i,f ; LSB additionmovf j+1,w ; w← j (MSB)addwfc i+1,f ;MSB additionMSByte, use add with carryV 0.1 1016-bit Increment/DecrementOn the PIC18, the increment/decrement instructions affectthe Carry flag, so can do increment/decrement of LSBytefollowed by add-with-carry/subtract-with-borrow to MSByte.On the PIC16, the increment/decrement instructions onlyaffect the Z flag, so cannot use C flag approach if incf/decfused (can always just do add + 1). Use the procedure below:0x33 FF0x34 00+ 1- 10x34 000x33 FFIf LSByte = 0 after increment,then increment MSbyteIf LSByte = 0 before increment,then decrement MSbyteV 0.1 11C codeint i;i++;LSByte incrementif Z=0, continueZ=1, so MSByteincrement16-bit IncrementPIC16 assemblyCBLOCK 0x040i:2ENDC;; i++;incf i,f ; i(LSB)+ 1btfsc STATUS,Z;Z=0?incf i+1,f ;i MSB ← i MSB + 1skip...continue...V 0.1 122