Trap – Texas Instruments TMS320C2XX User Manual

Page 345

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TRAP

Software Interrupt

7-192

Syntax

TRAP

Operands

None

Opcode

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1

0

0

0

1

0

1

0

0

1

1

1

1

1

0

1

Execution

(PC) + 1

stack

22h

PC

Status Bits

Not affected by INTM; does not affect INTM.

Description

The TRAP instruction is a software interrupt that transfers program control to
program-memory location 22h and pushes the program counter (PC) plus 1
onto the hardware stack. The instruction at location 22h may contain a branch
instruction to transfer control to the TRAP routine. Putting (PC + 1) onto the
stack enables a return instruction to pop the return address (which points to
the instruction after TRAP) from the stack. The TRAP instruction is not mask-
able.

Words

1

Cycles for a Single TRAP Instruction

ROM

DARAM

SARAM

External

4

4

4

4+3p

† The processor performs speculative fetching by reading two additional instruction words. If the

PC discontinuity is taken, these two instruction words are discarded.

Example

TRAP

;PC + 1 is pushed onto the stack, and then

;control is passed to program memory location

;22h.

Cycles

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