COREMP7 Datasheet, PDF (10/30 Pages) Actel Corporation – CoreMP7

CoreMP7
The Relationship Between ARM State and Thumb State Registers
The Thumb state registers relate to the ARM state registers in the following way:
• Thumb state r0–r7 and ARM state r0–r7 are identical.
• Thumb state CPSR and SPSR, and ARM state CPSR and SPSR are identical.
• Thumb state SP maps onto ARM state r13.
• Thumb state LR maps onto ARM state r14.
• The Thumb state PC maps onto the ARM state PC (r15).
These relationships are shown in Figure 6.
Thumb State
r0
r1
r2
r3
r4
r5
r6
r7
Stack Pointer (PC)
Link Register (LR)
Program Counter (PC)
Current Program Status Register
(CPSR)
ARM State
r0
r1
r2
r3
r4
r5
r6
r7
r8
r9
r10
r11
r12
Stack Pointer (r13)
Link Register (r14)
Program Counter (r15)
Current Program Status Register
(CPSR)
Saved Program Status Register
(SPSR)
Saved Program Status Register
(SPSR)
Figure 6 • Mapping of Thumb State Registers to ARM State Registers
Note: Registers r0–r7 are known as the low registers. Registers r8–r15 are known as the high registers.
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