8.92 --global_reg=reg_name[,reg_name,...]

Treats the specified register names as fixed registers, and prevents the compiler from generating code that uses these registers.

Note:

Try to avoid using this option, because it restricts the compiler in terms of register allocation and can potentially give a negative effect on code generation and performance.

Syntax

--global_reg=reg_name[,reg_name,...]

Where reg_name is the AAPCS name of the register, denoted by an integer value in the range 1 to 8.

Register names 1 to 8 map sequentially onto registers r4 to r11.

If reg_name is unspecified, the compiler faults use of --global_reg.

Restrictions

This option has the same restrictions as the __global_reg storage class specifier.

Example

--global_reg=1,4,5

Reserves registers r4, r7 and r8

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