Assembler Language Reference

tw or t (Trap Word) Instruction

Purpose

Generates a program interrupt when a specified condition is true.

Syntax

Bits	Value
0-5	31
6-10	TO
11-15	RA
16-20	RB
21-30	4
31	/

PowerPC
tw	TO, RA, RB

POWER family
t	TO, RA, RB

See Extended Mnemonics of Fixed-Point Trap Instructions for more information.

Description

The tw and t instructions compare the contents of general-purpose register (GPR) RA with the contents of GPR RB, AND the compared results with TO, and generate a trap-type Program Interrupt if the result is not 0.

The TO bit conditions are defined as follows.

TO bit	ANDed with Condition
0	Compares Less Than.
1	Compares Greater Than.
2	Compares Equal.
3	Compares Logically Less Than.
4	Compares Logically Greater Than.

The tw and t instructions have one syntax form and do not affect the Fixed-Point Exception Register or Condition Register Field 0.

Parameters

TO	Specifies TO bits that are ANDed with compare results.
RA	Specifies source general-purpose register for compare.
RB	Specifies source general-purpose register for compare.

Examples

The following code generates a Program Interrupt:

# Assume GPR 4 contains 0x9000 3000.
# Assume GPR 7 contains 0x789A 789B.
tw 0x10,4,7
# A trap type Program Interrupt occurs.

Related Information

Branch Processor .

Fixed-Point Trap Instructions .