Datasheet

Differences

-proc, -arch

Select processor or architecture. Use

-cpu

instead.

-zasnum

Align structures on at least a

num

-byte boundary (1, 2, 4, or 8). The

default is now 1 (align only as strictly as the contents of the

structure require).

Impact

You can still output DWARF1 debug tables. However, the functionality of these output

files when used with the new debuggers might be reduced. Use DWARF2 format for

new projects and update your existing tools to use the DWARF2 format.

Obsolete ARM-specific language extensions

The following language extensions are obsolete:

__global_freg

This language extension is not required.

___weak (three underscores)

This was a synonym for

__weak

(two underscores) in SDT 2.50/2.51. Use

__weak

__softfp

This is a storage class specifier you can use in the declaration of a

function to indicate that the function has a software floating-point

interface (a

double

parameter passed in two integer registers, a

double

result returned in a0, a1) even though its implementation may use

floating-point instructions. Use this to create ARM-state, VFP-using (or

FPA-using) functions that you can call directly from Thumb state (in

Thumb state, floating-point instructions are inaccessible).

Obsolete and new predefined macros

The obsolete predefined macros are listed in Table 2-2.

Table 2-2 Obsolete predefined macros

Predefine Status Comments

__CLK_TCK

Obsolete C library use only.

__APCS_32

Obsolete Relates to obsolete APCS/TPCS. No ATPCS equivalent.

__APCS_FPREGARGS

Obsolete Relates to obsolete APCS/TPCS. No ATPCS equivalent.

__APCS_NOFP

Obsolete Relates to obsolete APCS/TPCS. No ATPCS equivalent.