12.6 Assembler changes between RVCT v3.1 and RVCT v4.0

Various changes have been made to armasm in RVCT v4.0.

The following changes to the assembler have been made:

  • The -O command-line option is deprecated. -O is a synonym for -o to output to a named file. This has been deprecated to avoid user confusion with the armcc option with the same name.

  • The -D command-line option is obsolete. Use --depend instead.

  • LDM r0!,{r0-r4} no longer ignores writeback. Previously in Thumb, LDM r0!,{r0-r4} assembled with a warning to the 16-bit encoded LDM instruction and no writeback was performed. Because the syntax requests writeback, and this encoding is only available when 32-bit encoded Thumb instructions are supported, it produces an error. To get the 16-bit encoded Thumb instruction you must remove the writeback.

  • The logical operator | is deprecated because it can cause problems with substitution of variables in source. The assembler warns on the first use of | as a logical operator. Use the :OR: operator instead.

Non-ConfidentialPDF file icon PDF versionARM DUI0530M
Copyright © 2010-2016 ARM Limited or its affiliates. All rights reserved.