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125 lines
3.1 KiB
Plaintext
125 lines
3.1 KiB
Plaintext
This chapter documents the backend for the Atari Jaguar GPU/DSP RISC processor.
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@section Legal
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This module is written in 2014-2015 by Frank Wille and
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is covered by the vasm copyright without modifications.
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@section Additional options for this module
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This module provides the following additional options:
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@table @option
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@item -big
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Output big-endian code and data (default).
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@item -little
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Output little-endian code and data.
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@item -many
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Generate code for GPU or DSP RISC. All instructions are accepted
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(default).
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@item -mdsp
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@itemx -mjerry
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Generate code for the DSP RISC (part of Jerry).
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@item -mgpu
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@itemx -mtom
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Generate code for the GPU RISC (part of Tom).
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@end table
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@section General
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This backend accepts RISC instructions for the GPU or DSP in Atari's
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Jaguar custom chip set according to the "Jaguar Technical Reference Manual
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for Tom & Jerry", Revision 8. Documentation bugs were fixed by using
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various sources on the net.
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The target address type is 32 bits.
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Default alignment for instructions is 2 bytes.
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Data is aligned to its natural alignment by default.
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@section Optimizations
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This backend performs the following optimizations and translations for
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the GPU/DSP RISC instruction set:
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@itemize @minus
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@item @code{load (Rn+0),Rm} is optimized to @code{load (Rn),Rm}.
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@item @code{store Rn,(Rm+0)} is optimized to @code{store Rn,(Rm)}.
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@end itemize
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@section Extensions
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This backend extends the selected syntax module by the following
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directives (note that a leading dot is optional):
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@table @code
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@item <symbol> ccdef <expression>
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Allows defining a symbol for the condition codes used in @code{jump}
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and @code{jr} instructions. Must be constant number in the range of
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0 to 31 or another condition code symbol.
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@item ccundef <symbol>
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Undefine a condition code symbol previously defined via @code{ccdef}.
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@item dsp
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Select DSP instruction set.
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@item <symbol> equr <Rn>
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Define a new symbol named <symbol> and assign the address register
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@code{Rn} to it. <Rn> may also be another register symbol.
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Note that a register symbol must be defined before it can be used.
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@item equrundef <symbol>
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Undefine a register symbol previously defined via @code{equr}.
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@item gpu
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Select GPU instruction set.
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@item <symbol> regequ <Rn>
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Equivalent to @code{equr}.
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@item regundef <symbol>
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Undefine a register symbol previously defined via @code{regequ}.
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@end table
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All directives may be optionally preceded by a dot (@code{.}), for
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compatibility with various syntax modules.
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@section Known Problems
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Some known problems of this module at the moment:
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@itemize @minus
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@item Encoding of @code{MOVEI} instruction in little-endian mode is unkown.
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@item The developer has to provide the necessary @code{NOP} instructions
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after jumps, or @code{OR} instructions to work around hardware bugs,
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her/himself.
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@end itemize
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@section Error Messages
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This module has the following error messages:
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@itemize @minus
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@item 2001: data size %d not supported
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@item 2002: value from %ld to %ld required
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@end itemize
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