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CHAPTER 3 REGISTERS
■ Program Status (PS) Flags
The program status flags are explained below.
•H flag
This flag is 1 if a carry from bit 3 to bit 4 or a borrow from bit 4 to bit 3 is generated as the result of an
operation, and it is 0 in other cases. Because it is used for decimal compensation instructions, it cannot
be guaranteed if it is used for applications other than addition or subtraction.
•I flag
An interrupt is enabled when this flag is 1 and is disabled when it is 0. It is set to 0 at reset which results
in the interrupt disabled state.
•IL1, IL0
These bits indicate the level of the currently-enabled interrupt. The interrupt is processed only when an
interrupt request with a value less than that indicated by these bits is issued.
•N flag
This flag is 1 when the most significant bit is 1 and is 0 when it is 0 as the result of an operation.
•Z flag
This flag is 1 when the most significant bit is 0 and is 0 in other cases as the result of an operation.
•V flag
Table 3.4-1 Conversion Rule for Actual Address of Direct Addressing and Bit
Direct Addressing
Operand address Direct bank pointer (DP) Actual address
00
H
to 7F
H
0000
H
to 007F
H
80
H
to FF
H
000
0080
H
to 00FF
H
001
0100
H
to 017F
H
010
0180
H
to 01FF
H
011
0200
H
to 027F
H
100
0280
H
to 02FF
H
101
0300
H
to 037F
H
110
0380
H
to 03FF
H
111
0400
H
to 047F
H
IL1 IL0 Interrupt level High and low
0 0 0 Highest
Lowest
01 1
10 2
11 3