150 lines
3.8 KiB
Text
150 lines
3.8 KiB
Text
@c Copyright (C) 2015-2022 Free Software Foundation, Inc.
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@c This is part of the GAS manual.
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@c For copying conditions, see the file as.texinfo.
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@c man end
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@ifset GENERIC
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@page
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@node PRU-Dependent
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@chapter PRU Dependent Features
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@end ifset
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@cindex PRU support
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@menu
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* PRU Options:: Options
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* PRU Syntax:: Syntax
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* PRU Relocations:: Relocations
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* PRU Directives:: PRU Machine Directives
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* PRU Opcodes:: Opcodes
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@end menu
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@node PRU Options
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@section Options
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@cindex PRU options
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@cindex options for PRU
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@c man begin OPTIONS
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@table @gcctabopt
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@cindex @code{mlink-relax} command-line option, PRU
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@item -mlink-relax
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Assume that LD would optimize LDI32 instructions by checking the upper
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16 bits of the @var{expression}. If they are all zeros, then LD would
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shorten the LDI32 instruction to a single LDI. In such case @code{@value{AS}}
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will output DIFF relocations for diff expressions.
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@cindex @code{mno-link-relax} command-line option, PRU
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@item -mno-link-relax
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Assume that LD would not optimize LDI32 instructions. As a consequence,
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DIFF relocations will not be emitted.
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@cindex @code{mno-warn-regname-label} command-line option, PRU
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@item -mno-warn-regname-label
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Do not warn if a label name matches a register name. Usually assembler
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programmers will want this warning to be emitted. C compilers may want
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to turn this off.
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@end table
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@c man end
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@node PRU Syntax
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@section Syntax
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@menu
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* PRU Chars:: Special Characters
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@end menu
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@node PRU Chars
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@subsection Special Characters
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@cindex line comment character, PRU
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@cindex PRU line comment character
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@samp{#} and @samp{;} are the line comment characters.
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@node PRU Relocations
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@section PRU Machine Relocations
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@cindex machine relocations, PRU
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@cindex PRU machine relocations
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@table @code
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@cindex @code{pmem} directive, PRU
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@item %pmem(@var{expression})
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Convert @var{expression} from byte-address to a
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word-address. In other words, shift right by two.
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@item %label(@var{expression})
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Mark the given operand as a label. This is useful if you need to jump to
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a label that matches a register name.
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@smallexample
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@group
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r1:
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jmp r1 ; Will jump to register R1
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jmp %label(r1) ; Will jump to label r1
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@end group
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@end smallexample
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@end table
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@node PRU Directives
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@section PRU Machine Directives
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@cindex machine directives, PRU
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@cindex PRU machine directives
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@table @code
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@cindex @code{align} directive, PRU
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@item .align @var{expression} [, @var{expression}]
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This is the generic @code{.align} directive, however
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this aligns to a power of two.
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@cindex @code{word} directive, PRU
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@item .word @var{expression}
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Create an aligned constant 4 bytes in size.
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@cindex @code{dword} directive, PRU
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@item .dword @var{expression}
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Create an aligned constant 8 bytes in size.
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@cindex @code{2byte} directive, PRU
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@item .2byte @var{expression}
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Create an unaligned constant 2 bytes in size.
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@cindex @code{4byte} directive, PRU
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@item .4byte @var{expression}
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Create an unaligned constant 4 bytes in size.
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@cindex @code{8byte} directive, PRU
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@item .8byte @var{expression}
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Create an unaligned constant 8 bytes in size.
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@cindex @code{16byte} directive, PRU
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@item .16byte @var{expression}
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Create an unaligned constant 16 bytes in size.
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@cindex @code{set no_warn_regname_label} directive, PRU
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@item .set no_warn_regname_label
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Do not output warnings when a label name matches a register name. Equivalent
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to passing the @code{-mno-warn-regname-label} command-line option.
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@end table
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@node PRU Opcodes
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@section Opcodes
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@cindex PRU opcodes
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@cindex opcodes for PRU
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@code{@value{AS}} implements all the standard PRU core V3 opcodes in the
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original pasm assembler. Older cores are not supported by @code{@value{AS}}.
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GAS also implements the LDI32 pseudo instruction for loading a 32-bit
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immediate value into a register.
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@smallexample
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ldi32 sp, __stack_top
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ldi32 r14, 0x12345678
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@end smallexample
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