UPD75236 datasheet(39/192 Pages) RENESAS

39 / 192 page

µPD75236

(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

MOV1

mem* .bit CY

MOV1 CY, mem* .bit

AND1 CY, mem* .bit

OR1 CY,

mem* .bit

XOR1 CY, mem* .bit

During interrupt execution

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

UPD75236 Datasheet(PDF) 39 Page - Renesas Technology Corp

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