IP2022 User’s Manual—Instruction Set Architecture www.ubicom.com 213 SUB fr,W Subtract W from fr into fr Operation: fr = fr - W Bits affected: C, DC, Z Opcode: 0000 101f ffff ffff Description: This instruction subtracts the contents of W 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 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