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2 interrupt service table (ist), Figure 5−1. interrupt service table – Texas Instruments TMS320C67X/C67X+ DSP User Manual

Page 401

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Overview

Interrupts

5-6

SPRU733

5.1.2 Interrupt Service Table (IST)

When the CPU begins processing an interrupt, it references the interrupt
service table (IST). The IST is a table of fetch packets that contain code for
servicing the interrupts. The IST consists of 16 consecutive fetch packets.
Each interrupt service fetch packet (ISFP) contains eight instructions. A simple
interrupt service routine may fit in an individual fetch packet.

The addresses and contents of the IST are shown in Figure 5−1. Because
each fetch packet contains eight 32-bit instruction words (or 32 bytes), each
address in the table is incremented by 32 bytes (20h) from the one adjacent
to it.

Figure 5−1. Interrupt Service Table

000h
020h
040h
060h
080h

0A0h

0C0h

0E0h

100h
120h
140h
160h
180h

1A0h

1C0h

1E0h

Program memory

RESET ISFP

NMI ISFP
Reserved
Reserved

INT4 ISFP
INT5 ISFP
INT6 ISFP
INT7 ISFP
INT8 ISFP
INT9 ISFP

INT10 ISFP

INT11 ISFP

INT12 ISFP
INT13 ISFP
INT14 ISFP
INT15 ISFP