PXD10RM Datasheet, PDF(780/1332 Page) Freescale Semiconductor, Inc – PXD10 Microcontroller

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PXD10RM Datasheet, PDF (780/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

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21.7.2.1 Software Vector Mode

interrupt_exception_handler:

code to create stack frame, save working register, and save SRR0 and SRR1

lis

r3,INTC_IACKR@ha

# form adjusted upper half of INTC_IACKR address

lwz

r3,INTC_IACKR@l(r3)

# load INTC_IACKR, which clears request to processor

lwz

r3,0x0(r3)

# load address of ISR from vector table

wrteei 1

# enable processor recognition of interrupts

code to save rest of context required by e500 EABI

mtlr

r3

blrl

# move INTC_IACKR contents into link register

# branch to ISR; link register updated with epilog

# address

epilog:

code to restore most of context required by e500 EABI

# Popping the LIFO after the restoration of most of the context and the disabling of processor

# recognition of interrupts eases the calculation of the maximum stack depth at the cost of

# postponing the servicing of the next interrupt request.

mbar

# ensure store to clear flag bit has completed

lis

r3,INTC_EOIR@ha

# form adjusted upper half of INTC_EOIR address

li

r4,0x0

# form 0 to write to INTC_EOIR

wrteei 0

# disable processor recognition of interrupts

stw

r4,INTC_EOIR@l(r3)

# store to INTC_EOIR, informing INTC to lower priority

code to restore SRR0 and SRR1, restore working registers, and delete stack frame

rfi

vector_table_base_address:

address of ISR for interrupt with vector 0

address of ISR for interrupt with vector 1

.

.

.

address of ISR for interrupt with vector 510

address of ISR for interrupt with vector 511

ISRx:

code to service the interrupt event

code to clear flag bit which drives interrupt request to INTC

blr # return to epilog

21.7.2.2 Hardware Vector Mode

This interrupt exception handler is useful with processor and system bus implementations which support

a hardware vector. This example assumes that each interrupt_exception_handlerx only has space for four

instructions, and therefore a branch to interrupt_exception_handler_continuedx is needed.

interrupt_exception_handlerx:

b interrupt_exception_handler_continuedx# 4 instructions available, branch to continue

21-28

PXD10 Microcontroller Reference Manual, Rev. 1

PreliminaryâSubject to Change Without Notice

Freescale Semiconductor

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