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Add explanation of how EXPORT works

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Fixes #608
This commit is contained in:
ISSOtm
2020-12-08 21:07:24 +01:00
parent 213d985e17
commit 4de6266442
1 changed files with 45 additions and 3 deletions
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48
src/asm/rgbasm.5
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@@ -930,13 +930,55 @@ The following will cause
and so on to be accessible to other files during the link process: and so on to be accessible to other files during the link process:
.Dl Ic EXPORT Ar symbol1 Bq , Ar symbol2 , No ... .Dl Ic EXPORT Ar symbol1 Bq , Ar symbol2 , No ...
.Pp .Pp
For example, if you have the following three files:
.Pp
.Ql a.asm :
.Bd -literal -compact
SECTION "a", WRAM0
LabelA:
.Ed
.Pp
.Ql b.asm :
.Bd -literal -compact
SECTION "b", WRAM0
ExportedLabelB1::
ExportedLabelB2:
EXPORT ExportedLabelB2
.Ed
.Pp
.Ql c.asm :
.Bd -literal -compact
SECTION "C", ROM0[0]
dw LabelA
dw ExportedLabelB1
dw ExportedLabelB2
.Ed
.Pp
Then
.Ql c.asm
can use
.Ql ExportedLabelB1
and
.Ql ExportedLabelB2 ,
but not
.Ql LabelA ,
so linking them together will fail:
.Bd -literal
$ rgbasm -o a.o a.asm
$ rgbasm -o b.o b.asm
$ rgbasm -o c.o c.asm
$ rgblink a.o b.o c.o
error: c.asm(2): Unknown symbol "LabelA"
Linking failed with 1 error
.Ed
.Pp
Note also that only exported symbols will appear in symbol and map files produced by
.Xr rgblink 1 .
.Pp
.Ic GLOBAL .Ic GLOBAL
is a deprecated synonym for is a deprecated synonym for
.Ic EXPORT , .Ic EXPORT ,
do not use it. do not use it.
.Pp
Note also that only exported symbols will appear in symbol and map files produced by
.Xr rgblink 1 .
.Ss Purging symbols .Ss Purging symbols
.Ic PURGE .Ic PURGE
allows you to completely remove a symbol from the symbol table as if it had never existed. allows you to completely remove a symbol from the symbol table as if it had never existed.