1991-04-05 02:19:56 +08:00
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The GAS Configuration Plan
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Theory:
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1996-06-29 00:38:05 +08:00
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The goal of the new configuration scheme is to bury all object format
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and target processor dependancies in object and target specific files.
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That is, to move all #ifdef's out of the gas common code.
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1991-04-05 02:19:56 +08:00
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Here's how it works. There is a .h and a .c file for each object file
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1996-06-29 00:38:05 +08:00
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format and a .h and a .c file for each target processor. The
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configure script creates symlinks in the current directory to the
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appropriate files in the config directory. configure also serves as a
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list of triplets {host, target, object-format} that have been tested
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at one time or another. I also recommend that configure be used to
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document triplet specific notes as to purpose of the triplet, etc.
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1991-04-05 02:19:56 +08:00
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Implementation:
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obj-format.h is a {sym}link to .../config/obj-something.h. It is intended
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All gas .c files include as.h.
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as.h #define's "gas", includes host.h, defines a number of gas
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specific structures and types, and then includes tp.h, obj.h, and
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target-environment.h.
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target-environment.h defines a target environment specific
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preprocessor flag, eg, TE_SUN, and then includes obj-format.h.
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obj-format.h defines an object format specific preprocessor flag, eg,
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OBJ_AOUT, OBJ_BOUT, OBJ_COFF, includes "target-processor.h", and then
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defines the object specific macros, functions, types, and structures.
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target-processor.h
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target-processor.
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Porting:
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There appear to be four major types of ports; new hosts, new target
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processors, new object file formats, and new target environments.
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