Computers as Components, 2nd Edition

2.3 TI C55x DSP 85

The C55x provides two types of subroutine returns: fast-return and slow-

return. These vary on where they store the return address and loop context. In a

slow return, the return address and loop context are stored on the stack. In a fast

return, these two values are stored in registers: the return address register and the

control flow context register.

Interrupts use the basic subroutine call mechanism. They are processed in

four phases:

1. The interrupt request is received.

2. The interrupt request is acknowledged.

3. Prepare for the interrupt service routine by finishing execution of the current

instruction, storing registers, and