D17133CS datasheet(114/289 Pages) NEC

114 / 289 page

CHAPTER 11

ARITHMETIC AND LOGIC UNIT

11.6 COMPARISON JUDGEMENT

As shown in Table 11-7, there are comparison judgement instructions for determining if one value is "equal to",

"not equal to", "greater than or equal to", or "less than" another.

The SKE instruction is used to determine if two values are equal. The SKNE instruction is used to determine two

values are not equal. The SKGE instruction is used to determine if one value is greater than or equal to another and

the SKLT instruction is used to determine if one value is less than another.

The SKE, SKNE, SKGE, and SKLT instructions perform comparisons between a value in data memory and

immediate data. In order to compare values in the general register and data memory, a subtraction instruction is

performed according to the values in the CMP and Z flags in the program status word (PSWORD). For more

information concerning comparison of the general register and data memory, refer to 11.3.

Comparison judgements are not affected by the BCD or CMP flags in the program status word (PSWORD) and

comparison judgements do not cause either the CY or Z flags in the program status word (PSWORD) to be set.

11.6.1 to 11.6.4 explain the "equal to", "not equal to", "greater than or equal to", and "less than" comparison

judgements.

Table 11-7. Comparison Judgement Instructions

Comparison

Equal to

judgement

SKE m, #n4

Not equal to

SKNE m, #n4

Greater than or equal to

SKGE m, #n4

Less than

SKLT m, #n4

D17133CS Datasheet(PDF) 114 Page - NEC