ColdFire Core
MCF52110 ColdFire® Integrated Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor
3-17
Preliminary
3.3.3.1
Exception Stack Frame Definition
shows exception stack frame. The first longword contains the 16-bit format/vector word (F/V)
and the 16-bit status register, and the second longword contains the 32-bit program counter address.
The 16-bit format/vector word contains three unique fields:
•
A 4-bit format field at the top of the system stack is always written with a value of 4, 5, 6, or 7 by
the processor, indicating a two-longword frame format. See
.
•
There is a 4-bit fault status field, FS[3:0], at the top of the system stack. This field is defined for
access and address errors only and written as zeros for all other exceptions. See
.
•
The 8-bit vector number, vector[7:0], defines the exception type and is calculated by the processor
for all internal faults and represents the value supplied by the interrupt controller in case of an
interrupt. See
31 30 29 28
27
26
25 24 23 22 21 20 19 18
17
16
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
SSP
→
Format
FS[3:2]
Vector
FS[1:0]
Status Register
+ 0x4
Program Counter
Figure 3-16. Exception Stack Frame Form
Table 3-6. Format Field Encodings
Original SSP @ Time
of Exception, Bits 1:0
SSP @ 1st
Instruction of
Handler
Format Field
00
Original SSP - 8
0100
01
Original SSP - 9
0101
10
Original SSP - 10
0110
11
Original SSP - 11
0111
Table 3-7. Fault Status Encodings
FS[3:0]
Definition
00
xx
Reserved
0100
Error on instruction fetch
0101
Reserved
011x
Reserved
1000
Error on operand write
1001
Attempted write to write-protected space
101x
Reserved
1100
Error on operand read
1101
Reserved
111x
Reserved
