HD64336901G Renesas Technology, HD64336901G Datasheet - Page 45

• Manufacturer Part Number: HD64336901G
• Description: (HD64xxx Series) 16-BIT MICROCONTROLLER
• Manufacturer: Renesas Technology

Bit
7
6
5
4
3
2
1
0
Bit Name
I
UI
H
U
N
Z
V
C
Initial
Value
1
Undefined R/W
Undefined R/W
Undefined R/W
Undefined R/W
Undefined R/W
Undefined R/W
Undefined R/W
R/W
R/W
Description
Interrupt Mask Bit
Masks interrupts other than NMI when set to 1. NMI is
accepted regardless of the I bit setting. The I bit is set to
1 at the start of an exception-handling sequence.
User Bit
Can be written and read by software using the LDC, STC,
ANDC, ORC, and XORC instructions.
Half-Carry Flag
When the ADD.B, ADDX.B, SUB.B, SUBX.B, CMP.B, or
NEG.B instruction is executed, this flag is set to 1 if there
is a carry or borrow at bit 3, and cleared to 0 otherwise.
When the ADD.W, SUB.W, CMP.W, or NEG.W
instruction is executed, the H flag is set to 1 if there is a
carry or borrow at bit 11, and cleared to 0 otherwise.
When the ADD.L, SUB.L, CMP.L, or NEG.L instruction is
executed, the H flag is set to 1 if there is a carry or
borrow at bit 27, and cleared to 0 otherwise.
User Bit
Can be written and read by software using the LDC, STC,
ANDC, ORC, and XORC instructions.
Negative Flag
Stores the value of the most significant bit of data as a
sign bit.
Zero Flag
Set to 1 to indicate zero data, and cleared to 0 to indicate
non-zero data.
Overflow Flag
Set to 1 when an arithmetic overflow occurs, and cleared
to 0 at other times.
Carry Flag
Set to 1 when a carry occurs, and cleared to 0 otherwise.
Used by:
The carry flag is also used as a bit accumulator by bit
manipulation instructions.
Add instructions, to indicate a carry
Subtract instructions, to indicate a borrow
Shift and rotate instructions, to indicate a carry
Rev. 1.00, 11/03, page 17 of 376