SAM7X128_14 Datasheet, PDF (41/662 Pages) ATMEL Corporation – ARM-based Flash MCU

11.2.4.3 Exception Types
The ARM7TDMI supports five types of exception and a privileged processing mode for each type. The types of exceptions
are:
 fast interrupt (FIQ)
 normal interrupt (IRQ)
 memory aborts (used to implement memory protection or virtual memory)
 attempted execution of an undefined instruction
 software interrupts (SWIs)
Exceptions are generated by internal and external sources.
More than one exception can occur in the same time.
When an exception occurs, the banked version of R14 and the SPSR for the exception mode are used to save state.
To return after handling the exception, the SPSR is moved to the CPSR, and R14 is moved to the PC. This can be done
in two ways:
 by using a data-processing instruction with the S-bit set, and the PC as the destination
 by using the Load Multiple with Restore CPSR instruction (LDM)
11.2.5 ARM Instruction Set Overview
The ARM instruction set is divided into:
 Branch instructions
 Data processing instructions
 Status register transfer instructions
 Load and Store instructions
 Coprocessor instructions
 Exception-generating instructions
ARM instructions can be executed conditionally. Every instruction contains a 4-bit condition code field (bit[31:28]).
Table 11-2 gives the ARM instruction mnemonic list.
Table 11-2.
Mnemonic
MOV
ADD
SUB
RSB
CMP
TST
AND
EOR
MUL
SMULL
SMLAL
MSR
B
BX
ARM Instruction Mnemonic List
Operation
Move
Add
Subtract
Reverse Subtract
Compare
Test
Logical AND
Logical Exclusive OR
Multiply
Sign Long Multiply
Signed Long Multiply Accumulate
Move to Status Register
Branch
Branch and Exchange
Mnemonic
CDP
MVN
ADC
SBC
RSC
CMN
TEQ
BIC
ORR
MLA
UMULL
UMLAL
MRS
BL
Operation
Coprocessor Data Processing
Move Not
Add with Carry
Subtract with Carry
Reverse Subtract with Carry
Compare Negated
Test Equivalence
Bit Clear
Logical (inclusive) OR
Multiply Accumulate
Unsigned Long Multiply
Unsigned Long Multiply Accumulate
Move From Status Register
Branch and Link
SAM7X Series [DATASHEET] 41
6120K–ATARM–11-Feb-14