gas/doc/c-z80.texi - third_party/binutils-gdb - Git at Google

 @c Copyright (C) 2011-2016 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 Z80-Dependent
 @chapter Z80 Dependent Features
 @end ifset


 @ifclear GENERIC
 @node Machine Dependencies
 @chapter Z80 Dependent Features
 @end ifclear

 @cindex Z80 support
 @menu
 * Z80 Options::              Options
 * Z80 Syntax::               Syntax
 * Z80 Floating Point::       Floating Point
 * Z80 Directives::           Z80 Machine Directives
 * Z80 Opcodes::              Opcodes
 @end menu

 @node Z80 Options
 @section Options
 @cindex Z80 options
 @cindex options for Z80
 The Zilog Z80 and Ascii R800 version of @code{@value{AS}} have a few machine
 dependent options.
 @table @option
 @cindex @code{-z80} command line option, Z80
 @item -z80
 Produce code for the Z80 processor. There are additional options to
 request warnings and error messages for undocumented instructions.
 @item  -ignore-undocumented-instructions
 @itemx -Wnud
 Silently assemble undocumented Z80-instructions that have been adopted
 as documented R800-instructions.
 @item  -ignore-unportable-instructions
 @itemx -Wnup
 Silently assemble all undocumented Z80-instructions.
 @item  -warn-undocumented-instructions
 @itemx -Wud
 Issue warnings for undocumented Z80-instructions that work on R800, do
 not assemble other undocumented instructions without warning.
 @item  -warn-unportable-instructions
 @itemx -Wup
 Issue warnings for other undocumented Z80-instructions, do not treat any
 undocumented instructions as errors.
 @item  -forbid-undocumented-instructions
 @itemx -Fud
 Treat all undocumented z80-instructions as errors.
 @item  -forbid-unportable-instructions
 @itemx -Fup
 Treat undocumented z80-instructions that do not work on R800 as errors.

 @cindex @code{-r800} command line option, Z80
 @item -r800
 Produce code for the R800 processor. The assembler does not support
 undocumented instructions for the R800.
 In line with common practice, @code{@value{AS}} uses Z80 instruction names
 for the R800 processor, as far as they exist.
 @end table

 @cindex Z80 Syntax
 @node Z80 Syntax
 @section Syntax
 The assembler syntax closely follows the 'Z80 family CPU User Manual' by
 Zilog.
 In expressions a single @samp{=} may be used as ``is equal to''
 comparison operator.

 Suffices can be used to indicate the radix of integer constants;
 @samp{H} or @samp{h} for hexadecimal, @samp{D} or @samp{d} for decimal,
 @samp{Q}, @samp{O}, @samp{q} or @samp{o} for octal, and @samp{B} for
 binary.

 The suffix @samp{b} denotes a backreference to local label.

 @menu
 * Z80-Chars::                Special Characters
 * Z80-Regs::                 Register Names
 * Z80-Case::                 Case Sensitivity
 @end menu

 @node Z80-Chars
 @subsection Special Characters

 @cindex line comment character, Z80
 @cindex Z80 line comment character
 The semicolon @samp{;} is the line comment character;

 If a @samp{#} appears as the first character of a line then the whole
 line is treated as a comment, but in this case the line could also be
 a logical line number directive (@pxref{Comments}) or a preprocessor
 control command (@pxref{Preprocessing}).

 @cindex line separator, Z80
 @cindex statement separator, Z80
 @cindex Z80 line separator
 The Z80 assembler does not support a line separator character.

 @cindex location counter, Z80
 @cindex hexadecimal prefix, Z80
 @cindex Z80 $
 The dollar sign @samp{$} can be used as a prefix for hexadecimal numbers
 and as a symbol denoting the current location counter.

 @cindex character escapes, Z80
 @cindex Z80, \
 A backslash @samp{\} is an ordinary character for the Z80 assembler.

 @cindex character constant, Z80
 @cindex single quote, Z80
 @cindex Z80 '
 The single quote @samp{'} must be followed by a closing quote. If there
 is one character in between, it is a character constant, otherwise it is
 a string constant.

 @node Z80-Regs
 @subsection Register Names
 @cindex Z80 registers
 @cindex register names, Z80

 The registers are referred to with the letters assigned to them by
 Zilog. In addition @command{@value{AS}} recognizes @samp{ixl} and
 @samp{ixh} as the least and most significant octet in @samp{ix}, and
 similarly @samp{iyl} and  @samp{iyh} as parts of @samp{iy}.

 @c The @samp{'} in @samp{ex af,af'} may be omitted.

 @node Z80-Case
 @subsection Case Sensitivity
 @cindex Z80, case sensitivity
 @cindex case sensitivity, Z80

 Upper and lower case are equivalent in register names, opcodes,
 condition codes  and assembler directives.
 The case of letters is significant in labels and symbol names. The case
 is also important to distinguish the suffix @samp{b} for a backward reference
 to a local label from the suffix @samp{B} for a number in binary notation.

 @node Z80 Floating Point
 @section Floating Point
 @cindex floating point, Z80
 @cindex Z80 floating point
 Floating-point numbers are not supported.

 @node Z80 Directives
 @section Z80 Assembler Directives

 @command{@value{AS}} for the Z80 supports some additional directives for
 compatibility with other assemblers.

 @cindex Z80-only directives
 These are the additional directives in @code{@value{AS}} for the Z80:

 @table @code
 @item db @var{expression}|@var{string}[,@var{expression}|@var{string}...]
 @itemx defb @var{expression}|@var{string}[,@var{expression}|@var{string}...]
 For each @var{string} the characters are copied to the object file, for
 each other @var{expression} the value is stored in one byte.
 A warning is issued in case of an overflow.

 @item dw @var{expression}[,@var{expression}...]
 @itemx defw @var{expression}[,@var{expression}...]
 For each @var{expression} the value is stored in two bytes, ignoring
 overflow.

 @item d24 @var{expression}[,@var{expression}...]
 @itemx def24 @var{expression}[,@var{expression}...]
 For each @var{expression} the value is stored in three bytes, ignoring
 overflow.

 @item d32 @var{expression}[,@var{expression}...]
 @itemx def32 @var{expression}[,@var{expression}...]
 For each @var{expression} the value is stored in four bytes, ignoring
 overflow.

 @item ds @var{count}[, @var{value}]
 @itemx defs @var{count}[, @var{value}]
 @c Synonyms for @code{ds.b},
 @c which should have been described elsewhere
 Fill @var{count} bytes in the object file with @var{value}, if
 @var{value} is omitted it defaults to zero.

 @item @var{symbol} equ @var{expression}
 @itemx @var{symbol} defl @var{expression}
 These directives set the value of @var{symbol} to @var{expression}. If
 @code{equ} is used, it is an error if @var{symbol} is already defined.
 Symbols defined with @code{equ} are not protected from redefinition.

 @item set
 This is a normal instruction on Z80, and not an assembler directive.

 @item psect @var{name}
 A synonym for @xref{Section}, no second argument should be given.
 @ignore

 The following attributes will possibly be recognized in the future
 @table @code
 @item abs
 The section is to be absolute. @code{@value{AS}} will issue an error
 message because it can not produce an absolute section.
 @item global
 The section is to be concatenated with other sections of the same name
 by the linker, this is the default.
 @item local
 The section is not global. @code{@value{AS}} will issue a warning if
 object file format is not soff.
 @item ovrld
 The section is to be overlapped with other sections of the same name by
 the linker. @code{@value{AS}} will issue an error message
 because it can not mark a section as such.
 @item pure
 The section is marked as read only.
 @end table
 @end ignore

 @end table

 @node Z80 Opcodes
 @section Opcodes
 In line with common practice, Z80 mnemonics are used for both the Z80 and
 the R800.

 In many instructions it is possible to use one of the half index
 registers (@samp{ixl},@samp{ixh},@samp{iyl},@samp{iyh}) in stead of an
 8-bit general purpose register. This yields instructions that are
 documented on the R800 and undocumented on the Z80.
 Similarly @code{in f,(c)} is documented on the R800 and undocumented on
 the Z80.

 The assembler also supports the following undocumented Z80-instructions,
 that have not been adopted in the R800 instruction set:
 @table @code
 @item out (c),0
 Sends zero to the port pointed to by register c.

 @item sli @var{m}
 Equivalent to @code{@var{m} = (@var{m}<<1)+1}, the operand @var{m} can
 be any operand that is valid for @samp{sla}. One can use @samp{sll} as a
 synonym for @samp{sli}.

 @item @var{op} (ix+@var{d}), @var{r}
 This is equivalent to

 @example
 ld @var{r}, (ix+@var{d})
 @var{opc} @var{r}
 ld (ix+@var{d}), @var{r}
 @end example

 The operation @samp{@var{opc}} may be any of @samp{res @var{b},},
 @samp{set @var{b},}, @samp{rl}, @samp{rlc}, @samp{rr}, @samp{rrc},
 @samp{sla}, @samp{sli}, @samp{sra} and @samp{srl}, and the register
 @samp{@var{r}} may be any of @samp{a}, @samp{b}, @samp{c}, @samp{d},
 @samp{e}, @samp{h} and @samp{l}.

 @item @var{opc} (iy+@var{d}), @var{r}
 As above, but with @samp{iy} instead of @samp{ix}.
 @end table

 The web site at @uref{http://www.z80.info} is a good starting place to
 find more information on programming the Z80.
	@c Copyright (C) 2011-2016 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 Z80-Dependent
	@chapter Z80 Dependent Features
	@end ifset


	@ifclear GENERIC
	@node Machine Dependencies
	@chapter Z80 Dependent Features
	@end ifclear

	@cindex Z80 support
	@menu
	* Z80 Options:: Options
	* Z80 Syntax:: Syntax
	* Z80 Floating Point:: Floating Point
	* Z80 Directives:: Z80 Machine Directives
	* Z80 Opcodes:: Opcodes
	@end menu

	@node Z80 Options
	@section Options
	@cindex Z80 options
	@cindex options for Z80
	The Zilog Z80 and Ascii R800 version of @code{@value{AS}} have a few machine
	dependent options.
	@table @option
	@cindex @code{-z80} command line option, Z80
	@item -z80
	Produce code for the Z80 processor. There are additional options to
	request warnings and error messages for undocumented instructions.
	@item -ignore-undocumented-instructions
	@itemx -Wnud
	Silently assemble undocumented Z80-instructions that have been adopted
	as documented R800-instructions.
	@item -ignore-unportable-instructions
	@itemx -Wnup
	Silently assemble all undocumented Z80-instructions.
	@item -warn-undocumented-instructions
	@itemx -Wud
	Issue warnings for undocumented Z80-instructions that work on R800, do
	not assemble other undocumented instructions without warning.
	@item -warn-unportable-instructions
	@itemx -Wup
	Issue warnings for other undocumented Z80-instructions, do not treat any
	undocumented instructions as errors.
	@item -forbid-undocumented-instructions
	@itemx -Fud
	Treat all undocumented z80-instructions as errors.
	@item -forbid-unportable-instructions
	@itemx -Fup
	Treat undocumented z80-instructions that do not work on R800 as errors.

	@cindex @code{-r800} command line option, Z80
	@item -r800
	Produce code for the R800 processor. The assembler does not support
	undocumented instructions for the R800.
	In line with common practice, @code{@value{AS}} uses Z80 instruction names
	for the R800 processor, as far as they exist.
	@end table

	@cindex Z80 Syntax
	@node Z80 Syntax
	@section Syntax
	The assembler syntax closely follows the 'Z80 family CPU User Manual' by
	Zilog.
	In expressions a single @samp{=} may be used as ``is equal to''
	comparison operator.

	Suffices can be used to indicate the radix of integer constants;
	@samp{H} or @samp{h} for hexadecimal, @samp{D} or @samp{d} for decimal,
	@samp{Q}, @samp{O}, @samp{q} or @samp{o} for octal, and @samp{B} for
	binary.

	The suffix @samp{b} denotes a backreference to local label.

	@menu
	* Z80-Chars:: Special Characters
	* Z80-Regs:: Register Names
	* Z80-Case:: Case Sensitivity
	@end menu

	@node Z80-Chars
	@subsection Special Characters

	@cindex line comment character, Z80
	@cindex Z80 line comment character
	The semicolon @samp{;} is the line comment character;

	If a @samp{#} appears as the first character of a line then the whole
	line is treated as a comment, but in this case the line could also be
	a logical line number directive (@pxref{Comments}) or a preprocessor
	control command (@pxref{Preprocessing}).

	@cindex line separator, Z80
	@cindex statement separator, Z80
	@cindex Z80 line separator
	The Z80 assembler does not support a line separator character.

	@cindex location counter, Z80
	@cindex hexadecimal prefix, Z80
	@cindex Z80 $
	The dollar sign @samp{$} can be used as a prefix for hexadecimal numbers
	and as a symbol denoting the current location counter.

	@cindex character escapes, Z80
	@cindex Z80, \
	A backslash @samp{\} is an ordinary character for the Z80 assembler.

	@cindex character constant, Z80
	@cindex single quote, Z80
	@cindex Z80 '
	The single quote @samp{'} must be followed by a closing quote. If there
	is one character in between, it is a character constant, otherwise it is
	a string constant.

	@node Z80-Regs
	@subsection Register Names
	@cindex Z80 registers
	@cindex register names, Z80

	The registers are referred to with the letters assigned to them by
	Zilog. In addition @command{@value{AS}} recognizes @samp{ixl} and
	@samp{ixh} as the least and most significant octet in @samp{ix}, and
	similarly @samp{iyl} and @samp{iyh} as parts of @samp{iy}.

	@c The @samp{'} in @samp{ex af,af'} may be omitted.

	@node Z80-Case
	@subsection Case Sensitivity
	@cindex Z80, case sensitivity
	@cindex case sensitivity, Z80

	Upper and lower case are equivalent in register names, opcodes,
	condition codes and assembler directives.
	The case of letters is significant in labels and symbol names. The case
	is also important to distinguish the suffix @samp{b} for a backward reference
	to a local label from the suffix @samp{B} for a number in binary notation.

	@node Z80 Floating Point
	@section Floating Point
	@cindex floating point, Z80
	@cindex Z80 floating point
	Floating-point numbers are not supported.

	@node Z80 Directives
	@section Z80 Assembler Directives

	@command{@value{AS}} for the Z80 supports some additional directives for
	compatibility with other assemblers.

	@cindex Z80-only directives
	These are the additional directives in @code{@value{AS}} for the Z80:

	@table @code
	@item db @var{expression}\|@var{string}[,@var{expression}\|@var{string}...]
	@itemx defb @var{expression}\|@var{string}[,@var{expression}\|@var{string}...]
	For each @var{string} the characters are copied to the object file, for
	each other @var{expression} the value is stored in one byte.
	A warning is issued in case of an overflow.

	@item dw @var{expression}[,@var{expression}...]
	@itemx defw @var{expression}[,@var{expression}...]
	For each @var{expression} the value is stored in two bytes, ignoring
	overflow.

	@item d24 @var{expression}[,@var{expression}...]
	@itemx def24 @var{expression}[,@var{expression}...]
	For each @var{expression} the value is stored in three bytes, ignoring
	overflow.

	@item d32 @var{expression}[,@var{expression}...]
	@itemx def32 @var{expression}[,@var{expression}...]
	For each @var{expression} the value is stored in four bytes, ignoring
	overflow.

	@item ds @var{count}[, @var{value}]
	@itemx defs @var{count}[, @var{value}]
	@c Synonyms for @code{ds.b},
	@c which should have been described elsewhere
	Fill @var{count} bytes in the object file with @var{value}, if
	@var{value} is omitted it defaults to zero.

	@item @var{symbol} equ @var{expression}
	@itemx @var{symbol} defl @var{expression}
	These directives set the value of @var{symbol} to @var{expression}. If
	@code{equ} is used, it is an error if @var{symbol} is already defined.
	Symbols defined with @code{equ} are not protected from redefinition.

	@item set
	This is a normal instruction on Z80, and not an assembler directive.

	@item psect @var{name}
	A synonym for @xref{Section}, no second argument should be given.
	@ignore

	The following attributes will possibly be recognized in the future
	@table @code
	@item abs
	The section is to be absolute. @code{@value{AS}} will issue an error
	message because it can not produce an absolute section.
	@item global
	The section is to be concatenated with other sections of the same name
	by the linker, this is the default.
	@item local
	The section is not global. @code{@value{AS}} will issue a warning if
	object file format is not soff.
	@item ovrld
	The section is to be overlapped with other sections of the same name by
	the linker. @code{@value{AS}} will issue an error message
	because it can not mark a section as such.
	@item pure
	The section is marked as read only.
	@end table
	@end ignore

	@end table

	@node Z80 Opcodes
	@section Opcodes
	In line with common practice, Z80 mnemonics are used for both the Z80 and
	the R800.

	In many instructions it is possible to use one of the half index
	registers (@samp{ixl},@samp{ixh},@samp{iyl},@samp{iyh}) in stead of an
	8-bit general purpose register. This yields instructions that are
	documented on the R800 and undocumented on the Z80.
	Similarly @code{in f,(c)} is documented on the R800 and undocumented on
	the Z80.

	The assembler also supports the following undocumented Z80-instructions,
	that have not been adopted in the R800 instruction set:
	@table @code
	@item out (c),0
	Sends zero to the port pointed to by register c.

	@item sli @var{m}
	Equivalent to @code{@var{m} = (@var{m}<<1)+1}, the operand @var{m} can
	be any operand that is valid for @samp{sla}. One can use @samp{sll} as a
	synonym for @samp{sli}.

	@item @var{op} (ix+@var{d}), @var{r}
	This is equivalent to

	@example
	ld @var{r}, (ix+@var{d})
	@var{opc} @var{r}
	ld (ix+@var{d}), @var{r}
	@end example

	The operation @samp{@var{opc}} may be any of @samp{res @var{b},},
	@samp{set @var{b},}, @samp{rl}, @samp{rlc}, @samp{rr}, @samp{rrc},
	@samp{sla}, @samp{sli}, @samp{sra} and @samp{srl}, and the register
	@samp{@var{r}} may be any of @samp{a}, @samp{b}, @samp{c}, @samp{d},
	@samp{e}, @samp{h} and @samp{l}.

	@item @var{opc} (iy+@var{d}), @var{r}
	As above, but with @samp{iy} instead of @samp{ix}.
	@end table

	The web site at @uref{http://www.z80.info} is a good starting place to
	find more information on programming the Z80.