IP2022 User’s Manual—Instruction Set Architecture www.ubicom.com 219 SUBC fr,W Subtract Carry,W from fr into fr Operation: fr = fr - C - W Bits affected: C, DC, Z Opcode: 0100 101f ffff ffff Description: This instruction subtracts the contents of W and
the  complement  of  the  C  bit  (which  indicates
borrow)  from  the  contents  of  the  specified  data
memory location and writes the 8-bit  result  into
the   same   data   memory   location.   W   is   left
unchanged. The register contents are treated as
unsigned values. If the result of subtraction is negative (W + C is
larger than fr), the C bit is cleared and the lower
eight  bits  of  the  result  are  written  to  the  data
memory location. Otherwise, the C bit is set. If there is a borrow from bit 3 to bit 4, the DC (digit
carry) bit is cleared. Otherwise, the bit is set. If the result of subtraction is zero, the Z bit is set.
Otherwise, the bit is cleared. Cycles: 1