106
N OTES ON USE
(2) Status flags in decimal mode
When decimal mode is selected (D = 1), the values of three of the flags in the status
register (the flags N, V, and Z) are invalid after a ADC or SBC instruction is executed.
The carry flag (C) is set to “1” if a carry is generated as a result of the calculation, or
is cleared to “0” if a borrow is generated. To determine whether a calculation has
generated a carry, the C flag must be initialized to “0” before each calculation. To check
for a borrow, the C flag must be initialized to “1” before each calculation.
Fig. 4.2.5 Status flags in decimal mode
4.2.4 JMP instruction
When using the JMP instruction in indirect addressing mode, do not specify the last address
on a page as an indirect address.
NOP instruction
ADC or SBC instruction
SEC, CLC, or CLD instruction
Set D flag to “1”
