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authorIan Lance Taylor <ian@airs.com>1997-12-22 11:09:36 +0000
committerIan Lance Taylor <ian@airs.com>1997-12-22 11:09:36 +0000
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+@c Copyright (C) 1997 Free Software Foundation, Inc.
+@c This is part of the GAS manual.
+@c For copying conditions, see the file as.texinfo.
+@ifset GENERIC
+@page
+@node D30V-Dependent
+@chapter D30V Dependent Features
+@end ifset
+@ifclear GENERIC
+@node Machine Dependencies
+@chapter D30V Dependent Features
+@end ifclear
+
+@cindex D30V support
+@menu
+* D30V-Opts:: D30V Options
+* D30V-Syntax:: Syntax
+* D30V-Float:: Floating Point
+* D30V-Opcodes:: Opcodes
+@end menu
+
+@node D30V-Opts
+@section D30V Options
+@cindex options, D30V
+@cindex D30V options
+The Mitsubishi D30V version of @code{@value{AS}} has a few machine
+dependent options.
+
+@table @samp
+@item -O
+The D30V can often execute two sub-instructions in parallel. When this option
+is used, @code{@value{AS}} will attempt to optimize its output by detecting when
+instructions can be executed in parallel.
+
+@item -n
+When this option is used, @code{@value{AS}} will issue a warning every
+time it adds a nop instruction.
+
+@item -N
+When this option is used, @code{@value{AS}} will issue a warning if it
+needs to insert a nop after a 32-bit multiply before a load or 16-bit
+multiply instruction.
+@end table
+
+@node D30V-Syntax
+@section Syntax
+@cindex D30V syntax
+@cindex syntax, D30V
+
+The D30V syntax is based on the syntax in Mitsubishi's D30V architecture manual.
+The differences are detailed below.
+
+@menu
+* D30V-Size:: Size Modifiers
+* D30V-Subs:: Sub-Instructions
+* D30V-Chars:: Special Characters
+* D30V-Guarded:: Guarded Execution
+* D30V-Regs:: Register Names
+* D30V-Addressing:: Addressing Modes
+@end menu
+
+
+@node D30V-Size
+@subsection Size Modifiers
+@cindex D30V size modifiers
+@cindex size modifiers, D30V
+The D30V version of @code{@value{AS}} uses the instruction names in the D30V
+Architecture Manual. However, the names in the manual are sometimes ambiguous.
+There are instruction names that can assemble to a short or long form opcode.
+How does the assembler pick the correct form? @code{@value{AS}} will always pick the
+smallest form if it can. When dealing with a symbol that is not defined yet when a
+line is being assembled, it will always use the long form. If you need to force the
+assembler to use either the short or long form of the instruction, you can append
+either @samp{.s} (short) or @samp{.l} (long) to it. For example, if you are writing
+an assembly program and you want to do a branch to a symbol that is defined later
+in your program, you can write @samp{bra.s foo}.
+Objdump and GDB will always append @samp{.s} or @samp{.l} to instructions which
+have both short and long forms.
+
+@node D30V-Subs
+@subsection Sub-Instructions
+@cindex D30V sub-instructions
+@cindex sub-instructions, D30V
+The D30V assembler takes as input a series of instructions, either one-per-line,
+or in the special two-per-line format described in the next section. Some of these
+instructions will be short-form or sub-instructions. These sub-instructions can be packed
+into a single instruction. The assembler will do this automatically. It will also detect
+when it should not pack instructions. For example, when a label is defined, the next
+instruction will never be packaged with the previous one. Whenever a branch and link
+instruction is called, it will not be packaged with the next instruction so the return
+address will be valid. Nops are automatically inserted when necessary.
+
+If you do not want the assembler automatically making these decisions, you can control
+the packaging and execution type (parallel or sequential) with the special execution
+symbols described in the next section.
+
+@node D30V-Chars
+@subsection Special Characters
+@cindex line comment character, D30V
+@cindex D30V line comment character
+@samp{;} and @samp{#} are the line comment characters.
+@cindex sub-instruction ordering, D30V
+@cindex D30V sub-instruction ordering
+Sub-instructions may be executed in order, in reverse-order, or in parallel.
+Instructions listed in the standard one-per-line format will be executed
+sequentially unless you use the @samp{-O} option.
+
+To specify the executing order, use the following symbols:
+@table @samp
+@item ->
+Sequential with instruction on the left first.
+
+@item <-
+Sequential with instruction on the right first.
+
+@item ||
+Parallel
+@end table
+
+The D30V syntax allows either one instruction per line, one instruction per line with
+the execution symbol, or two instructions per line. For example
+@table @code
+@item abs r2,r3 -> abs r4,r5
+Execute these sequentially. The instruction on the right is in the right
+container and is executed second.
+
+@item abs r2,r3 <- abs r4,r5
+Execute these reverse-sequentially. The instruction on the right is in the right
+container, and is executed first.
+
+@item abs r2,r3 || abs r4,r5
+Execute these in parallel.
+
+@item ldw r2,@@(r3,r4) ||
+@itemx mulx r6,r8,r9
+Two-line format. Execute these in parallel.
+
+@item mulx a0,r8,r9
+@itemx stw r2,@@(r3,r4)
+Two-line format. Execute these sequentially unless @samp{-O} option is
+used. If the @samp{-O} option is used, the assembler will determine if
+the instructions could be done in parallel (the above two instructions
+can be done in parallel), and if so, emit them as parallel instructions.
+The assembler will put them in the proper containers. In the above
+example, the assembler will put the @samp{stw} instruction in left
+container and the @samp{mulx} instruction in the right container.
+
+@item stw r2,@@(r3,r4) ->
+@itemx mulx a0,r8,r9
+Two-line format. Execute the @samp{stw} instruction followed by the
+@samp{mulx} instruction sequentially. The first instruction goes in the
+left container and the second instruction goes into right container.
+The assembler will give an error if the machine ordering constraints are
+violated.
+
+@item stw r2,@@(r3,r4) <-
+@itemx mulx a0,r8,r9
+Same as previous example, except that the @samp{mulx} instruction is
+executed before the @samp{stw} instruction.
+@end table
+
+@cindex symbol names, @samp{$} in
+@cindex @code{$} in symbol names
+Since @samp{$} has no special meaning, you may use it in symbol names.
+
+@node D30V-Guarded
+@subsection Guarded Execution
+@cindex D30V Guarded Execution
+@code{@value{AS}} supports the full range of guarded execution
+directives for each instruction. Just append the directive after the
+instruction proper. The directives are:
+
+@table @samp
+@item /tx
+Execute the instruction if flag f0 is true.
+@item /fx
+Execute the instruction if flag f0 is false.
+@item /xt
+Execute the instruction if flag f1 is true.
+@item /xf
+Execute the instruction if flag f1 is false.
+@item /tt
+Execute the instruction if both flags f0 and f1 are true.
+@item /tf
+Execute the instruction if flag f0 is true and flag f1 is false.
+@end table
+
+@node D30V-Regs
+@subsection Register Names
+@cindex D30V registers
+@cindex registers, D30V
+You can use the predefined symbols @samp{r0} through @samp{r63} to refer
+to the D30V registers. You can also use @samp{sp} as an alias for
+@samp{r63} and @samp{link} as an alias for @samp{r62}. The accumulators
+are @samp{a0} and @samp{a1}.
+
+The D30V also has predefined symbols for these control registers and status bits:
+@table @code
+@item psw
+Processor Status Word
+@item bpsw
+Backup Processor Status Word
+@item pc
+Program Counter
+@item bpc
+Backup Program Counter
+@item rpt_c
+Repeat Count
+@item rpt_s
+Repeat Start address
+@item rpt_e
+Repeat End address
+@item mod_s
+Modulo Start address
+@item mod_e
+Modulo End address
+@item iba
+Instruction Break Address
+@item f0
+Flag 0
+@item f1
+Flag 1
+@item f2
+Flag 2
+@item f3
+Flag 3
+@item f4
+Flag 4
+@item f5
+Flag 5
+@item f6
+Flag 6
+@item f7
+Flag 7
+@item s
+Same as flag 4 (saturation flag)
+@item v
+Same as flag 5 (overflow flag)
+@item va
+Same as flag 6 (sticky overflow flag)
+@item c
+Same as flag 7 (carry/borrow flag)
+@item b
+Same as flag 7 (carry/borrow flag)
+@end table
+
+@node D30V-Addressing
+@subsection Addressing Modes
+@cindex addressing modes, D30V
+@cindex D30V addressing modes
+@code{@value{AS}} understands the following addressing modes for the D30V.
+@code{R@var{n}} in the following refers to any of the numbered
+registers, but @emph{not} the control registers.
+@table @code
+@item R@var{n}
+Register direct
+@item @@R@var{n}
+Register indirect
+@item @@R@var{n}+
+Register indirect with post-increment
+@item @@R@var{n}-
+Register indirect with post-decrement
+@item @@-SP
+Register indirect with pre-decrement
+@item @@(@var{disp}, R@var{n})
+Register indirect with displacement
+@item @var{addr}
+PC relative address (for branch or rep).
+@item #@var{imm}
+Immediate data (the @samp{#} is optional and ignored)
+@end table
+
+@node D30V-Float
+@section Floating Point
+@cindex floating point, D30V
+@cindex D30V floating point
+The D30V has no hardware floating point, but the @code{.float} and @code{.double}
+directives generates @sc{ieee} floating-point numbers for compatibility
+with other development tools.
+
+@node D30V-Opcodes
+@section Opcodes
+@cindex D30V opcode summary
+@cindex opcode summary, D30V
+@cindex mnemonics, D30V
+@cindex instruction summary, D30V
+For detailed information on the D30V machine instruction set, see
+@cite{D30V Architecture: A VLIW Microprocessor for Multimedia Applications}
+(Mitsubishi Electric Corp.).
+@code{@value{AS}} implements all the standard D30V opcodes. The only changes are those
+described in the section on size modifiers
+