232 lines
5.1 KiB
Text
232 lines
5.1 KiB
Text
@c Copyright (C) 2008-2022 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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@ifset GENERIC
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@page
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@node LM32-Dependent
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@chapter LM32 Dependent Features
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@end ifset
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@ifclear GENERIC
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@node Machine Dependencies
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@chapter LM32 Dependent Features
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@end ifclear
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@cindex LM32 support
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@menu
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* LM32 Options:: Options
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* LM32 Syntax:: Syntax
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* LM32 Opcodes:: Opcodes
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@end menu
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@node LM32 Options
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@section Options
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@cindex LM32 options (none)
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@cindex options for LM32 (none)
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@table @code
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@cindex @code{-mmultiply-enabled} command-line option, LM32
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@item -mmultiply-enabled
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Enable multiply instructions.
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@cindex @code{-mdivide-enabled} command-line option, LM32
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@item -mdivide-enabled
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Enable divide instructions.
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@cindex @code{-mbarrel-shift-enabled} command-line option, LM32
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@item -mbarrel-shift-enabled
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Enable barrel-shift instructions.
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@cindex @code{-msign-extend-enabled} command-line option, LM32
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@item -msign-extend-enabled
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Enable sign extend instructions.
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@cindex @code{-muser-enabled} command-line option, LM32
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@item -muser-enabled
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Enable user defined instructions.
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@cindex @code{-micache-enabled} command-line option, LM32
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@item -micache-enabled
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Enable instruction cache related CSRs.
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@cindex @code{-mdcache-enabled} command-line option, LM32
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@item -mdcache-enabled
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Enable data cache related CSRs.
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@cindex @code{-mbreak-enabled} command-line option, LM32
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@item -mbreak-enabled
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Enable break instructions.
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@cindex @code{-mall-enabled} command-line option, LM32
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@item -mall-enabled
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Enable all instructions and CSRs.
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@end table
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@node LM32 Syntax
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@section Syntax
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@menu
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* LM32-Regs:: Register Names
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* LM32-Modifiers:: Relocatable Expression Modifiers
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* LM32-Chars:: Special Characters
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@end menu
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@node LM32-Regs
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@subsection Register Names
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@cindex LM32 register names
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@cindex register names, LM32
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LM32 has 32 x 32-bit general purpose registers @samp{r0},
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@samp{r1}, ... @samp{r31}.
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The following aliases are defined: @samp{gp} - @samp{r26},
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@samp{fp} - @samp{r27}, @samp{sp} - @samp{r28},
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@samp{ra} - @samp{r29}, @samp{ea} - @samp{r30},
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@samp{ba} - @samp{r31}.
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LM32 has the following Control and Status Registers (CSRs).
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@table @code
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@item IE
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Interrupt enable.
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@item IM
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Interrupt mask.
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@item IP
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Interrupt pending.
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@item ICC
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Instruction cache control.
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@item DCC
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Data cache control.
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@item CC
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Cycle counter.
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@item CFG
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Configuration.
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@item EBA
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Exception base address.
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@item DC
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Debug control.
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@item DEBA
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Debug exception base address.
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@item JTX
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JTAG transmit.
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@item JRX
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JTAG receive.
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@item BP0
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Breakpoint 0.
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@item BP1
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Breakpoint 1.
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@item BP2
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Breakpoint 2.
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@item BP3
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Breakpoint 3.
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@item WP0
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Watchpoint 0.
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@item WP1
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Watchpoint 1.
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@item WP2
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Watchpoint 2.
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@item WP3
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Watchpoint 3.
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@end table
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@node LM32-Modifiers
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@subsection Relocatable Expression Modifiers
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@cindex LM32 modifiers
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@cindex syntax, LM32
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The assembler supports several modifiers when using relocatable addresses
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in LM32 instruction operands. The general syntax is the following:
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@smallexample
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modifier(relocatable-expression)
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@end smallexample
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@table @code
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@cindex symbol modifiers
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@item lo
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This modifier allows you to use bits 0 through 15 of
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an address expression as 16 bit relocatable expression.
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@item hi
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This modifier allows you to use bits 16 through 23 of an address expression
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as 16 bit relocatable expression.
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For example
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@smallexample
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ori r4, r4, lo(sym+10)
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orhi r4, r4, hi(sym+10)
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@end smallexample
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@item gp
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This modified creates a 16-bit relocatable expression that is
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the offset of the symbol from the global pointer.
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@smallexample
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mva r4, gp(sym)
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@end smallexample
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@item got
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This modifier places a symbol in the GOT and creates a 16-bit
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relocatable expression that is the offset into the GOT of this
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symbol.
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@smallexample
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lw r4, (gp+got(sym))
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@end smallexample
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@item gotofflo16
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This modifier allows you to use the bits 0 through 15 of an
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address which is an offset from the GOT.
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@item gotoffhi16
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This modifier allows you to use the bits 16 through 31 of an
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address which is an offset from the GOT.
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@smallexample
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orhi r4, r4, gotoffhi16(lsym)
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addi r4, r4, gotofflo16(lsym)
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@end smallexample
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@end table
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@node LM32-Chars
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@subsection Special Characters
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@cindex line comment character, LM32
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@cindex LM32 line comment character
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The presence of a @samp{#} on a line indicates the start of a comment
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that extends to the end of the current line. Note that if a line
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starts with a @samp{#} character then it can also be a logical line
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number directive (@pxref{Comments}) or a preprocessor
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control command (@pxref{Preprocessing}).
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@cindex line separator, LM32
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@cindex statement separator, LM32
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@cindex LM32 line separator
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A semicolon (@samp{;}) can be used to separate multiple statements on
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the same line.
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@node LM32 Opcodes
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@section Opcodes
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@cindex LM32 opcode summary
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@cindex opcode summary, LM32
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@cindex mnemonics, LM32
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@cindex instruction summary, LM32
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For detailed information on the LM32 machine instruction set, see
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@url{http://www.latticesemi.com/products/intellectualproperty/ipcores/mico32/}.
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@code{@value{AS}} implements all the standard LM32 opcodes.
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