1@c Copyright (C) 2011-2020 Free Software Foundation, Inc. 2@c This is part of the GAS manual. 3@c For copying conditions, see the file as.texinfo. 4 5@ifset GENERIC 6@page 7@node Z80-Dependent 8@chapter Z80 Dependent Features 9@end ifset 10 11 12@ifclear GENERIC 13@node Machine Dependencies 14@chapter Z80 Dependent Features 15@end ifclear 16 17@cindex Z80 support 18@menu 19* Z80 Options:: Options 20* Z80 Syntax:: Syntax 21* Z80 Floating Point:: Floating Point 22* Z80 Directives:: Z80 Machine Directives 23* Z80 Opcodes:: Opcodes 24@end menu 25 26@node Z80 Options 27@section Command-line Options 28@cindex Z80 options 29@cindex options for Z80 30@c man begin OPTIONS 31@table @gcctabopt 32 33@cindex @code{-march=} command-line option, Z80 34@item -march=@var{CPU}[-@var{EXT}@dots{}][+@var{EXT}@dots{}] 35This option specifies the target processor. The assembler will issue 36an error message if an attempt is made to assemble an instruction which 37will not execute on the target processor. The following processor names 38are recognized: 39@code{z80}, 40@code{z180}, 41@code{ez80}, 42@code{gbz80}, 43@code{z80n}, 44@code{r800}. 45In addition to the basic instruction set, the assembler can be told to 46accept some extention mnemonics. For example, 47@code{-march=z180+sli+infc} extends @var{z180} with @var{SLI} instructions and 48@var{IN F,(C)}. The following extentions are currently supported: 49@code{full} (all known instructions), 50@code{adl} (ADL CPU mode by default, eZ80 only), 51@code{sli} (instruction known as @var{SLI}, @var{SLL} or @var{SL1}), 52@code{xyhl} (instructions with halves of index registers: @var{IXL}, @var{IXH}, 53@var{IYL}, @var{IYH}), 54@code{xdcb} (instructions like @var{RotOp (II+d),R} and @var{BitOp n,(II+d),R}), 55@code{infc} (instruction @var{IN F,(C)} or @var{IN (C)}), 56@code{outc0} (instruction @var{OUT (C),0}). 57Note that rather than extending a basic instruction set, the extention 58mnemonics starting with @code{-} revoke the respective functionality: 59@code{-march=z80-full+xyhl} first removes all default extentions and adds 60support for index registers halves only. 61 62If this option is not specified then @code{-march=z80+xyhl+infc} is assumed. 63 64@cindex @code{-local-prefix} command-line option, Z80 65@item -local-prefix=@var{prefix} 66Mark all labels with specified prefix as local. But such label can be 67marked global explicitly in the code. This option do not change default 68local label prefix @code{.L}, it is just adds new one. 69 70@cindex @code{-colonless} command-line option, Z80 71@item -colonless 72Accept colonless labels. All symbols at line begin are treated as labels. 73 74@cindex @code{-sdcc} command-line option, Z80 75@item -sdcc 76Accept assembler code produced by SDCC. 77 78@cindex @code{-fp-s} command-line option, Z80 79@item -fp-s=@var{FORMAT} 80Single precision floating point numbers format. Default: ieee754 (32 bit). 81 82@cindex @code{-fp-d} command-line option, Z80 83@item -fp-d=@var{FORMAT} 84Double precision floating point numbers format. Default: ieee754 (64 bit). 85@end table 86@c man end 87 88Floating point numbers formats. 89@table @option 90@item @code{ieee754} 91Single or double precision IEEE754 compatible format. 92 93@item @code{half} 94Half precision IEEE754 compatible format (16 bits). 95 96@item @code{single} 97Single precision IEEE754 compatible format (32 bits). 98 99@item @code{double} 100Double precision IEEE754 compatible format (64 bits). 101 102@item @code{zeda32} 10332 bit floating point format from z80float library by Zeda. 104 105@item @code{math48} 10648 bit floating point format from Math48 package by Anders Hejlsberg. 107@end table 108 109@cindex Z80 Syntax 110@node Z80 Syntax 111@section Syntax 112The assembler syntax closely follows the 'Z80 family CPU User Manual' by 113Zilog. 114In expressions a single @samp{=} may be used as ``is equal to'' 115comparison operator. 116 117Suffices can be used to indicate the radix of integer constants; 118@samp{H} or @samp{h} for hexadecimal, @samp{D} or @samp{d} for decimal, 119@samp{Q}, @samp{O}, @samp{q} or @samp{o} for octal, and @samp{B} for 120binary. 121 122The suffix @samp{b} denotes a backreference to local label. 123 124@menu 125* Z80-Chars:: Special Characters 126* Z80-Regs:: Register Names 127* Z80-Case:: Case Sensitivity 128* Z80-Labels:: Labels 129@end menu 130 131@node Z80-Chars 132@subsection Special Characters 133 134@cindex line comment character, Z80 135@cindex Z80 line comment character 136The semicolon @samp{;} is the line comment character; 137 138If a @samp{#} appears as the first character of a line then the whole 139line is treated as a comment, but in this case the line could also be 140a logical line number directive (@pxref{Comments}) or a preprocessor 141control command (@pxref{Preprocessing}). 142 143@cindex line separator, Z80 144@cindex statement separator, Z80 145@cindex Z80 line separator 146The Z80 assembler does not support a line separator character. 147 148@cindex location counter, Z80 149@cindex hexadecimal prefix, Z80 150@cindex Z80 $ 151The dollar sign @samp{$} can be used as a prefix for hexadecimal numbers 152and as a symbol denoting the current location counter. 153 154@cindex character escapes, Z80 155@cindex Z80, \ 156A backslash @samp{\} is an ordinary character for the Z80 assembler. 157 158@cindex character constant, Z80 159@cindex single quote, Z80 160@cindex Z80 ' 161The single quote @samp{'} must be followed by a closing quote. If there 162is one character in between, it is a character constant, otherwise it is 163a string constant. 164 165@node Z80-Regs 166@subsection Register Names 167@cindex Z80 registers 168@cindex register names, Z80 169 170The registers are referred to with the letters assigned to them by 171Zilog. In addition @command{@value{AS}} recognizes @samp{ixl} and 172@samp{ixh} as the least and most significant octet in @samp{ix}, and 173similarly @samp{iyl} and @samp{iyh} as parts of @samp{iy}. 174 175@c The @samp{'} in @samp{ex af,af'} may be omitted. 176 177@node Z80-Case 178@subsection Case Sensitivity 179@cindex Z80, case sensitivity 180@cindex case sensitivity, Z80 181 182Upper and lower case are equivalent in register names, opcodes, 183condition codes and assembler directives. 184The case of letters is significant in labels and symbol names. The case 185is also important to distinguish the suffix @samp{b} for a backward reference 186to a local label from the suffix @samp{B} for a number in binary notation. 187 188@node Z80-Labels 189@subsection Labels 190 191@cindex labels, Z80 192@cindex Z80 labels 193Labels started by @code{.L} acts as local labels. You may specify custom local 194label prefix by @code{-local-prefix} command-line option. 195Dollar, forward and backward local labels are supported. By default, all labels 196are followed by colon. 197Legacy code with colonless labels can be built with @code{-colonless} 198command-line option specified. In this case all tokens at line begin are treated 199as labels. 200 201@node Z80 Floating Point 202@section Floating Point 203@cindex floating point, Z80 204@cindex Z80 floating point 205Floating-point numbers of following types are supported: 206 207@table @option 208@item @code{ieee754} 209Supported half, single and double precision IEEE754 compatible numbers. 210 211@item @code{zeda32} 21232 bit floating point numbers from z80float library by Zeda. 213 214@item @code{math48} 21548 bit floating point numbers from Math48 package by Anders Hejlsberg. 216@end table 217 218@node Z80 Directives 219@section Z80 Assembler Directives 220@cindex Z80-only directives 221 222@command{@value{AS}} for the Z80 supports some additional directives for 223compatibility with other assemblers. 224 225These are the additional directives in @code{@value{AS}} for the Z80: 226 227@table @code 228@item @code{.assume ADL = @var{expression}} 229@cindex @code{.assume} directive, Z80 230Set ADL status for eZ80. Non-zero value enable compilation in ADL mode else 231used Z80 mode. ADL and Z80 mode produces incompatible object code. Mixing 232both of them within one binary may lead problems with disassembler. 233 234@item @code{db @var{expression}|@var{string}[,@var{expression}|@var{string}...]} 235@cindex @code{db} directive, Z80 236@itemx @code{defb @var{expression}|@var{string}[,@var{expression}|@var{string}...]} 237@cindex @code{defb} directive, Z80 238@itemx @code{defm @var{string}[,@var{string}...]} 239@cindex @code{defm} directive, Z80 240For each @var{string} the characters are copied to the object file, for 241each other @var{expression} the value is stored in one byte. 242A warning is issued in case of an overflow. 243Backslash symbol in the strings is generic symbol, it cannot be used as 244escape character. @xref{Ascii,,@code{.ascii}}. 245 246@item @code{dw @var{expression}[,@var{expression}...]} 247@cindex @code{dw} directive, Z80 248@itemx @code{defw @var{expression}[,@var{expression}...]} 249@cindex @code{defw} directive, Z80 250For each @var{expression} the value is stored in two bytes, ignoring 251overflow. 252 253@item @code{d24 @var{expression}[,@var{expression}...]} 254@cindex @code{d24} directive, Z80 255@itemx @code{def24 @var{expression}[,@var{expression}...]} 256@cindex @code{def24} directive, Z80 257For each @var{expression} the value is stored in three bytes, ignoring 258overflow. 259 260@item @code{d32 @var{expression}[,@var{expression}...]} 261@cindex @code{d32} directive, Z80 262@itemx @code{def32 @var{expression}[,@var{expression}...]} 263@cindex @code{def32} directive, Z80 264For each @var{expression} the value is stored in four bytes, ignoring 265overflow. 266 267@item @code{ds @var{count}[, @var{value}]} 268@cindex @code{ds} directive, Z80 269@itemx @code{defs @var{count}[, @var{value}]} 270@cindex @code{defs} directive, Z80 271@c Synonyms for @code{ds.b}, 272@c which should have been described elsewhere 273Fill @var{count} bytes in the object file with @var{value}, if 274@var{value} is omitted it defaults to zero. 275 276@item @code{@var{symbol} defl @var{expression}} 277@cindex @code{defl} directive, Z80 278The @code{defl} directive is like @code{.set} but with different 279syntax. @xref{Set,,@code{.set}}. 280It set the value of @var{symbol} to @var{expression}. Symbols defined 281with @code{defl} are not protected from redefinition. 282 283@item @code{@var{symbol} equ @var{expression}} 284@cindex @code{equ} directive, Z80 285The @code{equ} directive is like @code{.equiv} but with different 286syntax. @xref{Equiv, ,@code{.equiv}}. 287It set the value of @var{symbol} to @var{expression}. It is an error 288if @var{symbol} is already defined. Symbols defined with @code{equ} 289are not protected from redefinition. 290 291@item @code{psect @var{name}} 292@cindex @code{psect} directive, Z80 293A synonym for @code{.section}, no second argument should be given. 294@xref{Section,,@code{.section}}. 295 296@item @code{xdef @var{symbol}} 297@cindex @code{xdef} directive, Z80 298A synonym for @code{.global}, make @var{symbol} is visible to linker. 299@xref{Global,,@code{.global}}. 300 301@item @code{xref @var{name}} 302@cindex @code{xref} directive, Z80 303A synonym for @code{.extern} (@ref{Extern,,@code{.extern}}). 304@ignore 305 306The following attributes will possibly be recognized in the future 307@table @code 308@item abs 309The section is to be absolute. @code{@value{AS}} will issue an error 310message because it can not produce an absolute section. 311@item global 312The section is to be concatenated with other sections of the same name 313by the linker, this is the default. 314@item local 315The section is not global. @code{@value{AS}} will issue a warning if 316object file format is not soff. 317@item ovrld 318The section is to be overlapped with other sections of the same name by 319the linker. @code{@value{AS}} will issue an error message 320because it can not mark a section as such. 321@item pure 322The section is marked as read only. 323@end table 324@end ignore 325 326@end table 327 328@node Z80 Opcodes 329@section Opcodes 330In line with common practice, Z80 mnemonics are used for the Z80, 331Z80N, Z180, eZ80, Ascii R800 and the GameBoy Z80. 332 333In many instructions it is possible to use one of the half index 334registers (@samp{ixl},@samp{ixh},@samp{iyl},@samp{iyh}) in stead of an 3358-bit general purpose register. This yields instructions that are 336documented on the eZ80 and the R800, undocumented on the Z80 and 337unsupported on the Z180. 338Similarly @code{in f,(c)} is documented on the R800, undocumented on 339the Z80 and unsupported on the Z180 and the eZ80. 340 341The assembler also supports the following undocumented Z80-instructions, 342that have not been adopted in any other instruction set: 343@table @code 344@item out (c),0 345Sends zero to the port pointed to by register @code{C}. 346 347@item sli @var{m} 348Equivalent to @code{@var{m} = (@var{m}<<1)+1}, the operand @var{m} can 349be any operand that is valid for @samp{sla}. One can use @samp{sll} as a 350synonym for @samp{sli}. 351 352@item @var{op} (ix+@var{d}), @var{r} 353This is equivalent to 354 355@example 356ld @var{r}, (ix+@var{d}) 357@var{op} @var{r} 358ld (ix+@var{d}), @var{r} 359@end example 360 361The operation @samp{@var{op}} may be any of @samp{res @var{b},}, 362@samp{set @var{b},}, @samp{rl}, @samp{rlc}, @samp{rr}, @samp{rrc}, 363@samp{sla}, @samp{sli}, @samp{sra} and @samp{srl}, and the register 364@samp{@var{r}} may be any of @samp{a}, @samp{b}, @samp{c}, @samp{d}, 365@samp{e}, @samp{h} and @samp{l}. 366 367@item @var{op} (iy+@var{d}), @var{r} 368As above, but with @samp{iy} instead of @samp{ix}. 369@end table 370 371The web site at @uref{http://www.z80.info} is a good starting place to 372find more information on programming the Z80. 373 374You may enable or disable any of these instructions for any target CPU 375even this instruction is not supported by any real CPU of this type. 376Useful for custom CPU cores. 377