The EXPORT directive declares a symbol that can
be used by the linker to resolve symbol references in separate object
and library files. GLOBAL is a synonym for EXPORT.
Syntax
EXPORT {[WEAK]}
EXPORTsymbol{[SIZE=n]}
EXPORTsymbol{[type{,set}]}
EXPORTsymbol[attr{,type{,set}}{,SIZE=n}]
EXPORTsymbol[WEAK{,attr}{,type{,set}}{,SIZE=n}]
where:
symbolis the symbol name to export. The symbol name is case-sensitive. If
symbolWEAKsymbolsymbol[WEAK]is used withoutsymbolattrcan be any one of:
DYNAMICsets the ELF symbol visibility to
STV_DEFAULT.PROTECTEDsets the ELF symbol visibility to
STV_PROTECTED.HIDDENsets the ELF symbol visibility to
STV_HIDDEN.INTERNALsets the ELF symbol visibility to
STV_INTERNAL.
typespecifies the symbol type:
DATAsymbolCODEsymbolELFTYPE=nsymboln, wherencan be any number from0to15.
If unspecified, the assembler determines the most appropriate
type. Usually the assembler determines the correct type so there is no need to specify thetype.setspecifies the instruction set:
ARMsymbolTHUMBsymbol
If unspecified, the assembler determines the most appropriate set.
nspecifies the size and can be any 32-bit value. If the
SIZEattribute is not specified, the assembler calculates the size:For
PROCandFUNCTIONsymbols, the size is set to the size of the code until itsENDPorENDFUNC.For other symbols, the size is the size of instruction or data on the same source line. If there is no instruction or data, the size is zero.
Use EXPORT to give code in other files access
to symbols in the current file.
Use the [WEAK] attribute to inform the linker
that a different instance of symbol[WEAK] attribute with any of
the symbol visibility attributes.
AREA Example,CODE,READONLY
EXPORT DoAdd ; Export the function name
; to be used by external
; modules.
DoAdd ADD r0,r0,r1
Symbol visibility can be overridden for duplicate exports.
In the following example, the last EXPORT takes precedence
for both binding and visibility:
EXPORT SymA[WEAK] ; Export as weak-hidden
EXPORT SymA[DYNAMIC] ; SymA becomes non-weak dynamic.
The following examples show the use of the SIZE attribute:
EXPORT symA [SIZE=4] EXPORT symA [DATA, SIZE=4]
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