ARM Compiler toolchain v4.1 for µVision Using the Compiler

Using the Inline and Embedded Assemblers of the ARM Compiler
7.28 Inline assembler BL and SVC corrupted register list
The BL and SVC instructions of the inline assembler have the following format:
SVC{cond} svc_num, {input_param_list}, {output_value_list}, {corrupt_reg_list}
BL{cond} function, {input_param_list}, {output_value_list}, {corrupt_reg_list}
corrupt_reg_list specifies the physical registers that are corrupted by the called function. If the
condition flags are modified by the called function, you must specify the PSR in the corrupted
register list.
The BL and SVC instructions always corrupt lr.
If corrupt_reg_list is omitted then for BL and SVC, the registers r0-r3, lr and the PSR are
corrupted.
Only the branch instruction, B, can be used to jump to labels within a single C or C++ function.
By default, if you do not specify any corrupt_reg_list registers, r0 to r3, r14, and the PSR can
be corrupted.
Note
It is not possible to specify the lr, sp, or pc registers in the corrupt register list.
7.28.1 See also
Concepts
• Inline assembler function calls and branches in C and C++ code on page 7-29
• Compiler support for inline assembly language on page 7-4.
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