AN2109 Freescale Semiconductor / Motorola, AN2109 Datasheet - Page 21

Manufacturer Part Number

AN2109

Description

MPC555 Interrupts

Manufacturer

Freescale Semiconductor / Motorola

Datasheet

1.AN2109.pdf (56 pages)

Frame

Stack

New

Special care should be used in saving the LR. For normal application functions, the

LR is stored in the current stack frame and a new stack frame is created. However,

since an exception routine function can occur anytime, the normal LR save area

may already be in use. One solution is for exception routines to save the LR else-

where on the stack, such as in the local variables area.

EABI Stack Frame

Prior back chain

Local variables

gpr save area

CR save area

LR save area

fpr save area

Back chain

Freescale Semiconductor, Inc.

For More Information On This Product,

Table 15 EABI Stack Frame Organization

Rev. 0, 26 July 2001

MPC555 Interrupts

Go to: www.freescale.com

quired so stack frame is modulo 8 bytes)

CR, XER, LR, padding (if padding is re-

(Reserved for function called by ISR)

CAUTION

Volatile gprs (gpr0, gpr3:12)

Example ISR Stack Frame

Prior SP

MOTOROLA