Chapter 7. Exception Processing
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7-3
Supervisor/User Stack Pointers (A7 and OTHER_A7)
ColdFire processors inhibit sampling for interrupts during the first instruction of all
exception handlers. This allows any handler to effectively disable interrupts, if necessary,
by raising the interrupt mask level in the SR.
7.2 Supervisor/User Stack Pointers
(A7 and OTHER_A7)
The CF4e architecture supports two unique stack pointer (A7) registers—the supervisor
stack pointer (SSP) and the user stack pointer (USP). This support provides the required
isolation between operating modes as dictated by the virtual memory management scheme
provided by the memory management unit (MMU). Note that only the SSP is used during
creation of the exception stack frame.
The hardware implementation of these two programmable-visible 32-bit registers does not
uniquely identify one as the SSP and the other as the USP. Rather, the hardware uses one
13
034
Next
PC breakpoint debug interrupt
14
038
Fault
Format error
15
03C
Next
Uninitialized interrupt
16–23
040–05C
—
Reserved
24
060
Next
Spurious interrupt
25–31
064–07C
Next
Level 1–7 autovectored interrupts
32–47
080–0BC
Next
Trap #0–15 instructions
48
0C0
Fault
Floating-point branch on unordered
condition
49
0C4
NextFP or Fault
Floating-point inexact result
50
0C8
NextFP
Floating-point divide-by-zero
51
0CC
NextFP or Fault
Floating-point underflow
52
0D0
NextFP or Fault
Floating-point operand error
53
0D4
NextFP or Fault
Floating-point overflow
54
0D8
NextFP or Fault
Floating-point input not-a-number (NAN)
55
0DC
NextFP or Fault
Floating-point input denormalized
number
56–60
0E0–0F0
—
Reserved
61
0F4
Fault
Unsupported instruction
62–63
0F8–0FC
—
Reserved
64–255
100–3FC
Next
User-defined interrupts
1
‘Fault’ refers to the PC of the faulting instruction. ‘Next’ refers to the PC of the instruction immediately after the
faulting instruction. NextFP’ refers to the PC of the next floating-point instruction.
Table 7-1. Exception Vector Assignments (Continued)
Vector Numbers Vector Offset (Hex)
Stacked Program Counter
1
Assignment
F
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