Texas Instruments TMS320C6000 Series Reference Manual page 360

Example 7–1. Relocation of Interrupt Service Table
(a) Relocating the IST to 800h
1) Copy the IST, located between 0h and 200h, to the memory loca-
tion between 800h and A00h.
2) Write 800h to the ISTP register: MVK 800h, A2
ISTP = 800h = 1000 0000 0000b
(b) How the ISTP directs the CPU to the appropriate ISFP in the
relocated IST
Assume: IFR = BBC0h = 1011 1011 1100 0000b
IER = 1230h = 0001 0010 0011 0001b
2 enabled interrupts pending: INT9 and INT12
The 1s in the IFR indicate pending interrupts; the 1s in the IER indi-
cate the interrupts that are enabled. INT9 has a higher priority
than INT12, so HPEINT is encoded with the value for INT9, 01001b.
HPEINT corresponds to bits 9–5 of the ISTP:
ISTP = 1001 0010 0000b = 920h = address of INT9
The reset fetch packet must be located at address 0, but the rest of the IST can
be at any program memory location that is on a 256-word boundary. The loca-
tion of the IST is determined by the interrupt service table base (ISTB) field of
the ISTP. Example 7–1 shows the relationship of the ISTB to the table location.
MVC A2, ISTP
Overview of Interrupts
IST
0
RESET ISFP
800h
RESET ISFP
820h
NMI ISFP
840h
Reserved
860h
Reserved
880h
INT4 ISFP
8A0h
INT5 ISFP
8C0h
INT6 ISFP
8E0h
INT7 ISFP
900h
INT8 ISFP
920h
INT9 ISFP
940h
INT10 ISFP
96h0
INT11 ISFP
980h
INT12 ISFP
9A0h
INT13 ISFP
9C0h
INT14 ISFP
9E0h
INT15 ISFP
Program memory
Interrupts 7-9