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@c Copyright 1997, 2002, 2003, 2006, 2011 Free Software Foundation, Inc.

@c This is part of the GAS manual.

@c For copying conditions, see the file as.texinfo.

@node V850-Dependent

@chapter v850 Dependent Features

@cindex V850 support

@menu

* V850 Options::              Options

* V850 Syntax::               Syntax

* V850 Floating Point::       Floating Point

* V850 Directives::           V850 Machine Directives

* V850 Opcodes::              Opcodes

@end menu

@node V850 Options

@section Options

@cindex V850 options (none)

@cindex options for V850 (none)

@code{@value{AS}} supports the following additional command-line options

for the V850 processor family:

@cindex command line options, V850

@cindex V850 command line options

@table @code

@cindex @code{-wsigned_overflow} command line option, V850

@item -wsigned_overflow

Causes warnings to be produced when signed immediate values overflow the

space available for then within their opcodes.  By default this option

is disabled as it is possible to receive spurious warnings due to using

exact bit patterns as immediate constants.

@cindex @code{-wunsigned_overflow} command line option, V850

@item -wunsigned_overflow

Causes warnings to be produced when unsigned immediate values overflow

the space available for then within their opcodes.  By default this

option is disabled as it is possible to receive spurious warnings due to

using exact bit patterns as immediate constants.

@cindex @code{-mv850} command line option, V850

@item -mv850

Specifies that the assembled code should be marked as being targeted at

the V850 processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@cindex @code{-mv850e} command line option, V850

@item -mv850e

Specifies that the assembled code should be marked as being targeted at

the V850E processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@cindex @code{-mv850e1} command line option, V850

@item -mv850e1

Specifies that the assembled code should be marked as being targeted at

the V850E1 processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@cindex @code{-mv850any} command line option, V850

@item -mv850any

Specifies that the assembled code should be marked as being targeted at

the V850 processor but support instructions that are specific to the

extended variants of the process.  This allows the production of

binaries that contain target specific code, but which are also intended

to be used in a generic fashion.  For example libgcc.a contains generic

routines used by the code produced by GCC for all versions of the v850

architecture, together with support routines only used by the V850E

architecture.

@cindex @code{-mv850e2} command line option, V850

@item -mv850e2

Specifies that the assembled code should be marked as being targeted at

the V850E2 processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@cindex @code{-mv850e2v3} command line option, V850

@item -mv850e2v3

Specifies that the assembled code should be marked as being targeted at

the V850E2V3 processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@cindex @code{-mrelax} command line option, V850

@item -mrelax

Enables relaxation.  This allows the .longcall and .longjump pseudo

ops to be used in the assembler source code.  These ops label sections

of code which are either a long function call or a long branch.  The

assembler will then flag these sections of code and the linker will

attempt to relax them.

@end table

@node V850 Syntax

@section Syntax

@menu

* V850-Chars::                Special Characters

* V850-Regs::                 Register Names

@end menu

@node V850-Chars

@subsection Special Characters

@cindex line comment character, V850

@cindex V850 line comment character

@samp{#} is the line comment character.  If a @samp{#} appears as the

first character of a line, the whole line is treated as a comment, but

in this case the line can also be a logical line number directive

(@pxref{Comments}) or a preprocessor control command

(@pxref{Preprocessing}).

Two dashes (@samp{--}) can also be used to start a line comment.

@cindex line separator, V850

@cindex statement separator, V850

@cindex V850 line separator

The @samp{;} character can be used to separate statements on the same

line.

@node V850-Regs

@subsection Register Names

@cindex V850 register names

@cindex register names, V850

@code{@value{AS}} supports the following names for registers:

@table @code

@cindex @code{zero} register, V850

@item general register 0

r0, zero

@item general register 1

r1

@item general register 2

r2, hp

@cindex @code{sp} register, V850

@item general register 3

r3, sp

@cindex @code{gp} register, V850

@item general register 4

r4, gp

@cindex @code{tp} register, V850

@item general register 5

r5, tp

@item general register 6

r6

@item general register 7

r7

@item general register 8

r8

@item general register 9

r9

@item general register 10

r10

@item general register 11

r11

@item general register 12

r12

@item general register 13

r13

@item general register 14

r14

@item general register 15

r15

@item general register 16

r16

@item general register 17

r17

@item general register 18

r18

@item general register 19

r19

@item general register 20

r20

@item general register 21

r21

@item general register 22

r22

@item general register 23

r23

@item general register 24

r24

@item general register 25

r25

@item general register 26

r26

@item general register 27

r27

@item general register 28

r28

@item general register 29

r29

@cindex @code{ep} register, V850

@item general register 30

r30, ep

@cindex @code{lp} register, V850

@item general register 31

r31, lp

@cindex @code{eipc} register, V850

@item system register 0

eipc

@cindex @code{eipsw} register, V850

@item system register 1

eipsw

@cindex @code{fepc} register, V850

@item system register 2

fepc

@cindex @code{fepsw} register, V850

@item system register 3

fepsw

@cindex @code{ecr} register, V850

@item system register 4

ecr

@cindex @code{psw} register, V850

@item system register 5

psw

@cindex @code{ctpc} register, V850

@item system register 16

ctpc

@cindex @code{ctpsw} register, V850

@item system register 17

ctpsw

@cindex @code{dbpc} register, V850

@item system register 18

dbpc

@cindex @code{dbpsw} register, V850

@item system register 19

dbpsw

@cindex @code{ctbp} register, V850

@item system register 20

ctbp

@end table

@node V850 Floating Point

@section Floating Point

@cindex floating point, V850 (@sc{ieee})

@cindex V850 floating point (@sc{ieee})

The V850 family uses @sc{ieee} floating-point numbers.

@node V850 Directives

@section V850 Machine Directives

@cindex machine directives, V850

@cindex V850 machine directives

@table @code

@cindex @code{offset} directive, V850

@item .offset @var{<expression>}

Moves the offset into the current section to the specified amount.

@cindex @code{section} directive, V850

@item .section "name", <type>

This is an extension to the standard .section directive.  It sets the

current section to be <type> and creates an alias for this section

called "name".

@cindex @code{.v850} directive, V850

@item .v850

Specifies that the assembled code should be marked as being targeted at

the V850 processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@cindex @code{.v850e} directive, V850

@item .v850e

Specifies that the assembled code should be marked as being targeted at

the V850E processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@cindex @code{.v850e1} directive, V850

@item .v850e1

Specifies that the assembled code should be marked as being targeted at

the V850E1 processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@cindex @code{.v850e2} directive, V850

@item .v850e2

Specifies that the assembled code should be marked as being targeted at

the V850E2 processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@cindex @code{.v850e2v3} directive, V850

@item .v850e2v3

Specifies that the assembled code should be marked as being targeted at

the V850E2V3 processor.  This allows the linker to detect attempts to link

such code with code assembled for other processors.

@end table

@node V850 Opcodes

@section Opcodes

@cindex V850 opcodes

@cindex opcodes for V850

@code{@value{AS}} implements all the standard V850 opcodes.

@code{@value{AS}} also implements the following pseudo ops:

@table @code

@cindex @code{hi0} pseudo-op, V850

@item hi0()

Computes the higher 16 bits of the given expression and stores it into

the immediate operand field of the given instruction.  For example:

    @samp{mulhi hi0(here - there), r5, r6}

computes the difference between the address of labels 'here' and

'there', takes the upper 16 bits of this difference, shifts it down 16

bits and then multiplies it by the lower 16 bits in register 5, putting

the result into register 6.

@cindex @code{lo} pseudo-op, V850

@item lo()

Computes the lower 16 bits of the given expression and stores it into

the immediate operand field of the given instruction.  For example:

    @samp{addi lo(here - there), r5, r6}

computes the difference between the address of labels 'here' and

'there', takes the lower 16 bits of this difference and adds it to

register 5, putting the result into register 6.

@cindex @code{hi} pseudo-op, V850

@item hi()

Computes the higher 16 bits of the given expression and then adds the

value of the most significant bit of the lower 16 bits of the expression

and stores the result into the immediate operand field of the given

instruction.  For example the following code can be used to compute the

address of the label 'here' and store it into register 6:

    @samp{movhi hi(here), r0, r6}

    @samp{movea lo(here), r6, r6}

The reason for this special behaviour is that movea performs a sign

extension on its immediate operand.  So for example if the address of

'here' was 0xFFFFFFFF then without the special behaviour of the hi()

pseudo-op the movhi instruction would put 0xFFFF0000 into r6, then the

movea instruction would takes its immediate operand, 0xFFFF, sign extend

it to 32 bits, 0xFFFFFFFF, and then add it into r6 giving 0xFFFEFFFF

which is wrong (the fifth nibble is E).  With the hi() pseudo op adding

in the top bit of the lo() pseudo op, the movhi instruction actually

stores 0 into r6 (0xFFFF + 1 = 0x0000), so that the movea instruction

stores 0xFFFFFFFF into r6 - the right value.

@cindex @code{hilo} pseudo-op, V850

@item hilo()

Computes the 32 bit value of the given expression and stores it into

the immediate operand field of the given instruction (which must be a

mov instruction).  For example:

    @samp{mov hilo(here), r6}

computes the absolute address of label 'here' and puts the result into

register 6.

@cindex @code{sdaoff} pseudo-op, V850

@item sdaoff()

Computes the offset of the named variable from the start of the Small

Data Area (whoes address is held in register 4, the GP register) and

stores the result as a 16 bit signed value in the immediate operand

field of the given instruction.  For example:

      @samp{ld.w sdaoff(_a_variable)[gp],r6}

loads the contents of the location pointed to by the label '_a_variable'

into register 6, provided that the label is located somewhere within +/-

32K of the address held in the GP register.  [Note the linker assumes

that the GP register contains a fixed address set to the address of the

label called '__gp'.  This can either be set up automatically by the

linker, or specifically set by using the @samp{--defsym __gp=<value>}

command line option].

@cindex @code{tdaoff} pseudo-op, V850

@item tdaoff()

Computes the offset of the named variable from the start of the Tiny

Data Area (whoes address is held in register 30, the EP register) and

stores the result as a 4,5, 7 or 8 bit unsigned value in the immediate

operand field of the given instruction.  For example:

      @samp{sld.w tdaoff(_a_variable)[ep],r6}

loads the contents of the location pointed to by the label '_a_variable'

into register 6, provided that the label is located somewhere within +256

bytes of the address held in the EP register.  [Note the linker assumes

that the EP register contains a fixed address set to the address of the

label called '__ep'.  This can either be set up automatically by the

linker, or specifically set by using the @samp{--defsym __ep=<value>}

command line option].

@cindex @code{zdaoff} pseudo-op, V850

@item zdaoff()

Computes the offset of the named variable from address 0 and stores the

result as a 16 bit signed value in the immediate operand field of the

given instruction.  For example:

      @samp{movea zdaoff(_a_variable),zero,r6}

puts the address of the label '_a_variable' into register 6, assuming

that the label is somewhere within the first 32K of memory.  (Strictly

speaking it also possible to access the last 32K of memory as well, as

the offsets are signed).

@cindex @code{ctoff} pseudo-op, V850

@item ctoff()

Computes the offset of the named variable from the start of the Call

Table Area (whoes address is helg in system register 20, the CTBP

register) and stores the result a 6 or 16 bit unsigned value in the

immediate field of then given instruction or piece of data.  For

example:

     @samp{callt ctoff(table_func1)}

will put the call the function whoes address is held in the call table

at the location labeled 'table_func1'.

@cindex @code{longcall} pseudo-op, V850

@item .longcall @code{name}

Indicates that the following sequence of instructions is a long call

to function @code{name}.  The linker will attempt to shorten this call

sequence if @code{name} is within a 22bit offset of the call.  Only

valid if the @code{-mrelax} command line switch has been enabled.

@cindex @code{longjump} pseudo-op, V850

@item .longjump @code{name}

Indicates that the following sequence of instructions is a long jump

to label @code{name}.  The linker will attempt to shorten this code

sequence if @code{name} is within a 22bit offset of the jump.  Only

valid if the @code{-mrelax} command line switch has been enabled.

@end table

For information on the V850 instruction set, see @cite{V850

Family 32-/16-Bit single-Chip Microcontroller Architecture Manual} from NEC.

Ltd.