ml670100 Oki Semiconductor, ml670100 Datasheet - Page 33

• Manufacturer Part Number: ml670100
• Description: Ml670100 Is A High-performance 32-bit Microcontroller
• Manufacturer: Oki Semiconductor

2.7.3
2.7.4
The THUMB state registers relate to the ARM state registers in the following way:
This relationship is shown in Figure 2.4: Mapping of THUMB state registers onto ARM state
registers.
A value may be transferred from a register in the range R0-R7 (a Lo register) to a Hi register,
and from a Hi register to a Lo register, using special variants of the MOV instruction. Hi
register values can also be compared against or added to Lo register values with the CMP and
ADD instructions.
The relationship between ARM and THUMB state registers
Accessing Hi registers in THUMB state
In THUMB state, registers R8-R15 (the Hi registers) are not part of the standard register set.
However, the assembly language programmer has limited access to them, and can use them for
fast temporary storage.
• 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)
Figure 2.4 : Mapping of THUMB state registers onto ARM state registers
Program Counter (PC)
Stack Pointer (SP)
Link Register (LR)
THUMB State
CPSR
SPSR
R0
R1
R2
R3
R4
R5
R6
R7
Program Counter (R15)
Stack Pointer (R13)
Link Register (R14)
ARM State
CPSR
SPSR
R10
R11
R12
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
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