UPD17015GS datasheet(24/120 Pages) NEC

24 / 120 page

µPD17015

Fig. 5-3 Outline of Function of Each Flag of Program Status Word

Program status word

(PSWORD)

RPL

PSW

Zero flag

(Z)

Carry flag

(CY)

Compare flag

(CMP)

BCD flag

(BCD)

Used to indicate that the result of an arithmetic operation is 0.

Note that the states of 0 and 1 differ, depending on the value

of the compare flag.

Used to specify whether to store the result of an arithmetic

operation in a general-purpose register or data memory area.

0 : Stores the result.

1 : Does not store the result.

Used to specify whether to perform an arithmetic operation

in decimal.

0 : Performs a binary operation.

1 : Performs a decimal operation.

Used to indicate the ocurrence of a carry or borrow as the

result of an addition or subtraction instruction executed.

This flag is cleared to 0 when neither a carry nor a borrow

is produced.

This flag is set to 1 when a carry or borrow is produced.

This flag is used also as a shift bit for the RORC r instruction.

Flag name

Function

5.2.3

Notes on Using Program Status Word

When an arithmetic instruction (addition or subtraction) is executed for the program status word, the result of the

arithmetic operation is stored.

If an operation is performed which produces the result 0000B with a carry, for example, 0000B is stored in the

PSW.

5.3

NOTES ON USING SYSTEM REGISTER

Those data items in the program status word that are always set to 0 are not affected by an attempt to execute

a write instruction.

When those data items in the program status word that are always set to 0 are read, 0 is read.

UPD17015GS Datasheet(PDF) 24 Page - NEC

UPD17015GS Datasheet(HTML) 24 Page - NEC

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL