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authorTheo de Raadt <deraadt@cvs.openbsd.org>1995-10-18 08:53:40 +0000
committerTheo de Raadt <deraadt@cvs.openbsd.org>1995-10-18 08:53:40 +0000
commitd6583bb2a13f329cf0332ef2570eb8bb8fc0e39c (patch)
treeece253b876159b39c620e62b6c9b1174642e070e /gnu/usr.bin/gas/README.pic
initial import of NetBSD tree
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+A few short notes on PIC support.
+
+. References to the symbol "_GLOBAL_OFFSET_TABLE_" are special. These always
+ PC relative to the start of the current instruction. Also, they occur
+ in "complex" expressions in function prologs, eg.
+
+ move _GLOBAL_OFFSET_TABLE_ + (. - L1 ), %some_register
+
+ The expression parser can't handle these generically, so the expression
+ above is recognised as a special case.
+
+. Some archs have special PIC assembler syntax to reference static and global
+ data. This is handled in targ-cpu.c.
+
+. Correct relocation_info must be output (eg. fields r_jmptable and r_baserel).
+
+. Internal labels must be output in the symbol table if they are referred to
+ by PIC instructions. The linker must allocate a GOT slot for them.
+
+. The former meaning of the -k switch ("WORKING_DOT" stuff), has been nuked
+ in favour of enabling PIC code recognition.
+
+
+-pk
+