mirror of
https://github.com/espressif/binutils-gdb.git
synced 2025-08-06 14:49:38 +08:00
Add support for the Z80 processor family
This commit is contained in:
Nick Clifton
248
gas/doc/c-z80.texi
Normal file
248
gas/doc/c-z80.texi
Normal file
@ -0,0 +1,248 @@
|
||||
@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
|
||||
|
||||
@c DO-NOT-COMMIT
|
||||
|
||||
@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 instriction 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;
|
||||
|
||||
@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 inbetween, 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}} recognises @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, ignoring
|
||||
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 ds @var{count}[, @var{value}]
|
||||
@itemx defs @var{count}[, @var{value}]
|
||||
@c Synonyms for @code{ds.b},
|
||||
@c which should have been described elsewhre
|
||||
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}. To
|
||||
keep code portable to other assemblers it is best to use @samp{equ} for
|
||||
the first definition and @samp{defl} for redefinitions.
|
||||
|
||||
@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 recognised 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 commmon practice Z80 mnonics 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.
|
||||
|
||||
Reference in New Issue
Block a user