mirror of
https://github.com/autc04/Retro68.git
synced 2024-11-23 15:32:26 +00:00
268 lines
7.5 KiB
Plaintext
268 lines
7.5 KiB
Plaintext
@c Copyright (C) 2012-2017 Free Software Foundation, Inc.
|
|
@c This is part of the GAS manual.
|
|
@c For copying conditions, see the file as.texinfo.
|
|
@c man end
|
|
@ifset GENERIC
|
|
@page
|
|
@node NiosII-Dependent
|
|
@chapter Nios II Dependent Features
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter Nios II Dependent Features
|
|
@end ifclear
|
|
|
|
@cindex Altera Nios II support
|
|
@cindex Nios support
|
|
@cindex Nios II support
|
|
@menu
|
|
* Nios II Options:: Options
|
|
* Nios II Syntax:: Syntax
|
|
* Nios II Relocations:: Relocations
|
|
* Nios II Directives:: Nios II Machine Directives
|
|
* Nios II Opcodes:: Opcodes
|
|
@end menu
|
|
|
|
@node Nios II Options
|
|
@section Options
|
|
@cindex Nios II options
|
|
@cindex options for Nios II
|
|
|
|
@c man begin OPTIONS
|
|
@table @gcctabopt
|
|
|
|
@cindex @code{relax-section} command line option, Nios II
|
|
@item -relax-section
|
|
Replace identified out-of-range branches with PC-relative @code{jmp}
|
|
sequences when possible. The generated code sequences are suitable
|
|
for use in position-independent code, but there is a practical limit
|
|
on the extended branch range because of the length of the sequences.
|
|
This option is the default.
|
|
|
|
@cindex @code{relax-all} command line option, Nios II
|
|
@item -relax-all
|
|
Replace branch instructions not determinable to be in range
|
|
and all call instructions with @code{jmp} and @code{callr} sequences
|
|
(respectively). This option generates absolute relocations against the
|
|
target symbols and is not appropriate for position-independent code.
|
|
|
|
@cindex @code{no-relax} command line option, Nios II
|
|
@item -no-relax
|
|
Do not replace any branches or calls.
|
|
|
|
@cindex @code{EB} command line option, Nios II
|
|
@item -EB
|
|
Generate big-endian output.
|
|
|
|
@cindex @code{EL} command line option, Nios II
|
|
@item -EL
|
|
Generate little-endian output. This is the default.
|
|
|
|
@cindex @code{march} command line option, Nios II
|
|
@item -march=@var{architecture}
|
|
This option specifies the target architecture. The assembler issues
|
|
an error message if an attempt is made to assemble an instruction which
|
|
will not execute on the target architecture. The following architecture
|
|
names are recognized:
|
|
@code{r1},
|
|
@code{r2}.
|
|
The default is @code{r1}.
|
|
|
|
@end table
|
|
@c man end
|
|
|
|
@node Nios II Syntax
|
|
@section Syntax
|
|
@menu
|
|
* Nios II Chars:: Special Characters
|
|
@end menu
|
|
|
|
|
|
@node Nios II Chars
|
|
@subsection Special Characters
|
|
|
|
@cindex line comment character, Nios II
|
|
@cindex Nios II line comment character
|
|
@cindex line separator character, Nios II
|
|
@cindex Nios II line separator character
|
|
@samp{#} is the line comment character.
|
|
@samp{;} is the line separator character.
|
|
|
|
|
|
@node Nios II Relocations
|
|
@section Nios II Machine Relocations
|
|
|
|
@cindex machine relocations, Nios II
|
|
@cindex Nios II machine relocations
|
|
|
|
@table @code
|
|
@cindex @code{hiadj} directive, Nios II
|
|
@item %hiadj(@var{expression})
|
|
Extract the upper 16 bits of @var{expression} and add
|
|
one if the 15th bit is set.
|
|
|
|
The value of @code{%hiadj(@var{expression})} is:
|
|
@smallexample
|
|
((@var{expression} >> 16) & 0xffff) + ((@var{expression} >> 15) & 0x01)
|
|
@end smallexample
|
|
|
|
The @code{%hiadj} relocation is intended to be used with
|
|
the @code{addi}, @code{ld} or @code{st} instructions
|
|
along with a @code{%lo}, in order to load a 32-bit constant.
|
|
|
|
@smallexample
|
|
movhi r2, %hiadj(symbol)
|
|
addi r2, r2, %lo(symbol)
|
|
@end smallexample
|
|
|
|
@cindex @code{hi} directive, Nios II
|
|
@item %hi(@var{expression})
|
|
Extract the upper 16 bits of @var{expression}.
|
|
|
|
@cindex @code{lo} directive, Nios II
|
|
@item %lo(@var{expression})
|
|
Extract the lower 16 bits of @var{expression}.
|
|
|
|
@cindex @code{gprel} directive, Nios II
|
|
@item %gprel(@var{expression})
|
|
Subtract the value of the symbol @code{_gp} from
|
|
@var{expression}.
|
|
|
|
The intention of the @code{%gprel} relocation is
|
|
to have a fast small area of memory which only
|
|
takes a 16-bit immediate to access.
|
|
|
|
@smallexample
|
|
.section .sdata
|
|
fastint:
|
|
.int 123
|
|
.section .text
|
|
ldw r4, %gprel(fastint)(gp)
|
|
@end smallexample
|
|
|
|
@cindex @code{call} directive, Nios II
|
|
@cindex @code{call_lo} directive, Nios II
|
|
@cindex @code{call_hiadj} directive, Nios II
|
|
@cindex @code{got} directive, Nios II
|
|
@cindex @code{got_lo} directive, Nios II
|
|
@cindex @code{got_hiadj} directive, Nios II
|
|
@cindex @code{gotoff} directive, Nios II
|
|
@cindex @code{gotoff_lo} directive, Nios II
|
|
@cindex @code{gotoff_hiadj} directive, Nios II
|
|
@cindex @code{tls_gd} directive, Nios II
|
|
@cindex @code{tls_ie} directive, Nios II
|
|
@cindex @code{tls_le} directive, Nios II
|
|
@cindex @code{tls_ldm} directive, Nios II
|
|
@cindex @code{tls_ldo} directive, Nios II
|
|
@item %call(@var{expression})
|
|
@item %call_lo(@var{expression})
|
|
@item %call_hiadj(@var{expression})
|
|
@itemx %got(@var{expression})
|
|
@itemx %got_lo(@var{expression})
|
|
@itemx %got_hiadj(@var{expression})
|
|
@itemx %gotoff(@var{expression})
|
|
@itemx %gotoff_lo(@var{expression})
|
|
@itemx %gotoff_hiadj(@var{expression})
|
|
@itemx %tls_gd(@var{expression})
|
|
@itemx %tls_ie(@var{expression})
|
|
@itemx %tls_le(@var{expression})
|
|
@itemx %tls_ldm(@var{expression})
|
|
@itemx %tls_ldo(@var{expression})
|
|
|
|
These relocations support the ABI for Linux Systems documented in the
|
|
@cite{Nios II Processor Reference Handbook}.
|
|
@end table
|
|
|
|
|
|
@node Nios II Directives
|
|
@section Nios II Machine Directives
|
|
|
|
@cindex machine directives, Nios II
|
|
@cindex Nios II machine directives
|
|
|
|
@table @code
|
|
|
|
@cindex @code{align} directive, Nios II
|
|
@item .align @var{expression} [, @var{expression}]
|
|
This is the generic @code{.align} directive, however
|
|
this aligns to a power of two.
|
|
|
|
@cindex @code{half} directive, Nios II
|
|
@item .half @var{expression}
|
|
Create an aligned constant 2 bytes in size.
|
|
|
|
@cindex @code{word} directive, Nios II
|
|
@item .word @var{expression}
|
|
Create an aligned constant 4 bytes in size.
|
|
|
|
@cindex @code{dword} directive, Nios II
|
|
@item .dword @var{expression}
|
|
Create an aligned constant 8 bytes in size.
|
|
|
|
@cindex @code{2byte} directive, Nios II
|
|
@item .2byte @var{expression}
|
|
Create an unaligned constant 2 bytes in size.
|
|
|
|
@cindex @code{4byte} directive, Nios II
|
|
@item .4byte @var{expression}
|
|
Create an unaligned constant 4 bytes in size.
|
|
|
|
@cindex @code{8byte} directive, Nios II
|
|
@item .8byte @var{expression}
|
|
Create an unaligned constant 8 bytes in size.
|
|
|
|
@cindex @code{16byte} directive, Nios II
|
|
@item .16byte @var{expression}
|
|
Create an unaligned constant 16 bytes in size.
|
|
|
|
@cindex @code{set noat} directive, Nios II
|
|
@item .set noat
|
|
Allows assembly code to use @code{at} register without
|
|
warning. Macro or relaxation expansions
|
|
generate warnings.
|
|
|
|
@cindex @code{set at} directive, Nios II
|
|
@item .set at
|
|
Assembly code using @code{at} register generates
|
|
warnings, and macro expansion and relaxation are
|
|
enabled.
|
|
|
|
@cindex @code{set nobreak} directive, Nios II
|
|
@item .set nobreak
|
|
Allows assembly code to use @code{ba} and @code{bt}
|
|
registers without warning.
|
|
|
|
@cindex @code{set break} directive, Nios II
|
|
@item .set break
|
|
Turns warnings back on for using @code{ba} and @code{bt}
|
|
registers.
|
|
|
|
@cindex @code{set norelax} directive, Nios II
|
|
@item .set norelax
|
|
Do not replace any branches or calls.
|
|
|
|
@cindex @code{set relaxsection} directive, Nios II
|
|
@item .set relaxsection
|
|
Replace identified out-of-range branches with
|
|
@code{jmp} sequences (default).
|
|
|
|
@cindex @code{set relaxall} directive, Nios II
|
|
@item .set relaxsection
|
|
Replace all branch and call instructions with
|
|
@code{jmp} and @code{callr} sequences.
|
|
|
|
@cindex @code{set} directive, Nios II
|
|
@item .set @dots{}
|
|
All other @code{.set} are the normal use.
|
|
|
|
@end table
|
|
|
|
@node Nios II Opcodes
|
|
@section Opcodes
|
|
|
|
@cindex Nios II opcodes
|
|
@cindex opcodes for Nios II
|
|
@code{@value{AS}} implements all the standard Nios II opcodes documented in the
|
|
@cite{Nios II Processor Reference Handbook}, including the assembler
|
|
pseudo-instructions.
|