![](http://datasheet.mmic.net.cn/370000/UPD75236GJ_datasheet_16740772/UPD75236GJ_37.png)
37
μ
PD75236
(1)
Carry flag (CY)
The carry flag is a 1-bit flag to store the overflow and underflow generate information when a carry
operation instruction (ADDC, SUBC) is executed.
It has the bit accumulator function to execute Boolean algebraic operations with the data memory
specified by the bit address and to store the result.
Carry flag manipulation is carried out using a dedicated instruction irrespective of other PSW bits.
When RESET signal is generated, the carry flag becomes undefined.
Table 3-3 Carry Flag Manipulation Instructions
Remarks
mem
*
.bit indicates the following three bit manipulated addressing operations.
fmem.bit
pmem.@L
@H + mem.bit
(2)
Skip flags (SK2, SK1, SK0)
The skip flag is used to store the skipped state and is automatically set/reset when the CPU executes an
instruction.
The user cannot directly operate the skip flags as operands.
Instruction (Mnemonic)
Carry Flag Operation and Processing
SET1
CLR1
NOT1 CY
SKT
CY
CY
CY
MOV1
MOV1 CY, mem
*
.bit
mem
*
.bit CY
AND1 CY, mem
*
.bit
OR1 CY,
XOR1 CY, mem
*
.bit
mem
*
.bit
During interrupt execution
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RETI
CY set (1)
CY clear (0)
CY contents invert
SKip if CY contents are 1
CY contents transfer to the specified bit
Specified bit contents transfer to CY
Specified bit contents ANDed/ORed/XORed with CY contents and
the results set to CY
Parallel save of other PSW bits and 8 bits to the stack memory
Restore from the stack memory in parallel to other PSW bits
Carry flag manipu-
lation dedicated
instruction
Bit transfer
instruction
Bit Boolean
instruction
Interrupt service