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ARM 指 令 参 考
示 例
try
MOV r1, #0x1
; load the ‘lock taken’ value
LDREX r0, [LockAddr] ; load the lock value
CMP r0, #0
; is the lock free?
STREXEQ r0, r1, [LockAddr] ; try and claim the lock
CMPEQ r0, #0
; did this succeed?
BNE try
; no – try again
.... ; yes – we have the lock
不 正 确 的 示 例
LDREX r0, [r2,#96]! ; no offset allowed
STREX r11, r10, [r15] ; use of r15 not allowed
LDREXGT r6, r4, [r10] ; LDREX has only two registers in its syntax
STREX r3, r3, [r7] ; Rd must be distinct from Rn (and from Rm)
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