Samsung S3C2440A - Manual (Page 47)

PROGRAMMER'S MODEL S3C2440A RISC MICROPROCESSOR
2-6
The relationship between ARM and THUMB state registers
The relationship between ARM and THUMB state registers are as below:-
• 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.
R0
R1
R2
R3
R4
R5
R6
R7
Stack Pointer (SP)
Link register (LR)
Program Counter (PC)
CPSR
SPSR
R0
R1
R2
R3
R4
R5
R6
R7
R9
R8
R10
R11
R12
Stack Pointer (R13)
Link register (R14)
Program Counter (R15)
CPSR
SPSR
Lo-registers
Hi-registers
THUMB state ARM state
Figure 2-5. Mapping of THUMB State Registers onto ARM State Registers