The Relationship Between Arm And Thumb State Registers - Samsung S3C2500B User Manual

S3C2500B

2.7.3 THE RELATIONSHIP BETWEEN ARM 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 SPSRs and ARM state CPSR and SPSRs are identical
— THUMB state SP maps onto ARM state R13
— THUMB state LR maps onto ARM state R14
The THUMB state program counter maps onto the ARM state program counter (R15)
This relationship is shown in Figure 2-5.
Program Counter (PC)
Figure 2-5. Mapping of THUMB State Registers onto ARM State Registers
THUMB State
R0
R1
R2
R3
R4
R5
R6
R7
Stack Pointer (SP)
Link Register (LR)
CPSR
SPSR
PROGRAMMER' ' S MODEL
ARM State
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
Stack Pointer (R13)
Link Register (R14)
Program Counter (R15)
CPSR
SPSR
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