Hi All, Could any one of tell me what does the plus sign in the undermentioned denote.
LDR r3, [r0,+r1,LSL #1]
Without the plus sign its just a simple load instruction.
regards ashu
arm instruction query
Apr 30, 2013
2 Replies
AFAICT, this plus sign is just the unary positive operator, and it is used to stress the "offset" nature of r1.
formatting link
A5.2 Addressing Mode 2 - Load and Store Word or Unsigned Byte
- [, +/-, #] See Load and Store Word or Unsigned Byte - Scaled register offset on page A5-22.
Syntax One of: [, +/-, LSL #] [, +/-, LSR #] [, +/-, ASR #] [, +/-, ROR #] [, +/-, RRX] where: Specifies the register containing the base address. Specifies the register containing the offset to add to or subtract from Rn.
So your instruction would compute addr = r0 + (r1
denote.
A5-22.
Rn.
thanks so much Noob. The explanation really helped.
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