Samsung S3C2440A User Manual

Page 50

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S3C2440A RISC MICROPROCESSOR

PROGRAMMER'S MODEL

2-9

Table 2-1. PSR Mode Bit Values

M[4:0]

Mode

Visible THUMB state registers

Visible ARM state registers

10000 User R7..R0,

LR, SP
PC, CPSR

R14..R0,
PC, CPSR

10001 FIQ

R7..R0,
LR_fiq, SP_fiq
PC, CPSR, SPSR_fiq

R7..R0,
R14_fiq..R8_fiq,
PC, CPSR, SPSR_fiq

10010 IRQ

R7..R0,
LR_irq, SP_irq
PC, CPSR, SPSR_irq

R12..R0,
R14_irq, R13_irq,
PC, CPSR, SPSR_irq

10011 Supervisor

R7..R0,
LR_svc, SP_svc,
PC, CPSR, SPSR_svc

R12..R0,
R14_svc, R13_svc,
PC, CPSR, SPSR_svc

10111 Abort R7..R0,

LR_abt, SP_abt,
PC, CPSR, SPSR_abt

R12..R0,
R14_abt, R13_abt,
PC, CPSR, SPSR_abt

11011 Undefined

R7..R0
LR_und, SP_und,
PC, CPSR, SPSR_und

R12..R0,
R14_und, R13_und,
PC, CPSR

11111 System

R7..R0,
LR, SP
PC, CPSR

R14..R0,
PC, CPSR

Reserved bits The remaining bits in the PSR's are reserved. While changing a PSR's flag or control bits,

you must ensure that these unused bits are not altered. Also, your program should not rely

on them containing specific values, since in future processors they may read as one or

zero.

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