© 2000 Scenix Semiconductor, Inc. All rights reserved. 67 SX User’s Manual Rev. 3.1 www.scenix.com Chapter 3 Instruction Set 3.6.1 ADD fr,W Add W to fr Operation: fr = fr + W Bits affected: C, DC, Z Opcode: 0001 111f ffff Description: This instruction adds the contents of W to the contents of the specified file register
and writes the 8-bit result into the same file register. W is left unchanged. The reg-
ister contents are treated as unsigned values. If the result of addition exceeds FFh, the C bit is set and the lower eight bits of the
result are written to the file register. Otherwise, the C bit is cleared. If there is a carry from bit 3 to bit 4, the DC (digit carry) bit is set. Otherwise, the
bit is cleared. If the result of addition is 00h, the Z bit is set. Otherwise, the bit is cleared. An
addition result of 100h is considered zero and therefore sets the Z bit. Config. Option: If the CF bit in the FUSEX configuration register has been programmed to 0, this
instruction also adds the C bit as a carry-in input: fr = fr + W + C Cycles: 1 Example: add $12,W This example adds the contents of W to file register 12h. For example, if the file
register contains 7Fh  and W contains 02h, this  instruction adds 02h  to 7Fh  and
writes the result, 81h, into the file register; and clears the C and Z bits. It sets the
DC bit because of the carry from bit 3 to bit 4.