gas/doc/c-rl78.texi

   1 @c Copyright (C) 2011-2021 Free Software Foundation, Inc.
   2 @c This is part of the GAS manual.
   3 @c For copying conditions, see the file as.texinfo.
   4 @ifset GENERIC
   5 @page
   6 @node RL78-Dependent
   7 @chapter RL78 Dependent Features
   8 @end ifset
   9 @ifclear GENERIC
  10 @node Machine Dependencies
  11 @chapter RL78 Dependent Features
  12 @end ifclear
  13
  14 @cindex RL78 support
  15 @menu
  16 * RL78-Opts::                   RL78 Assembler Command-line Options
  17 * RL78-Modifiers::              Symbolic Operand Modifiers
  18 * RL78-Directives::             Assembler Directives
  19 * RL78-Syntax::                 Syntax
  20 @end menu
  21
  22 @node RL78-Opts
  23 @section RL78 Options
  24 @cindex options, RL78
  25 @cindex RL78 options
  26
  27 @table @code
  28 @item relax
  29 Enable support for link-time relaxation.
  30
  31 @item norelax
  32 Disable support for link-time relaxation (default).
  33
  34 @item mg10
  35 Mark the generated binary as targeting the G10 variant of the RL78
  36 architecture.
  37
  38 @item mg13
  39 Mark the generated binary as targeting the G13 variant of the RL78
  40 architecture.
  41
  42 @item mg14
  43 @itemx mrl78
  44 Mark the generated binary as targeting the G14 variant of the RL78
  45 architecture.  This is the default.
  46
  47 @item m32bit-doubles
  48 Mark the generated binary as one that uses 32-bits to hold the
  49 @code{double} floating point type.  This is the default.
  50
  51 @item m64bit-doubles
  52 Mark the generated binary as one that uses 64-bits to hold the
  53 @code{double} floating point type.
  54
  55 @end table
  56
  57 @node RL78-Modifiers
  58 @section Symbolic Operand Modifiers
  59
  60 @cindex RL78 modifiers
  61 @cindex syntax, RL78
  62
  63 The RL78 has three modifiers that adjust the relocations used by the
  64 linker:
  65
  66 @table @code
  67
  68 @item %lo16()
  69
  70 When loading a 20-bit (or wider) address into registers, this modifier
  71 selects the 16 least significant bits.
  72
  73 @smallexample
  74   movw ax,#%lo16(_sym)
  75 @end smallexample
  76
  77 @item %hi16()
  78
  79 When loading a 20-bit (or wider) address into registers, this modifier
  80 selects the 16 most significant bits.
  81
  82 @smallexample
  83   movw ax,#%hi16(_sym)
  84 @end smallexample
  85
  86 @item %hi8()
  87
  88 When loading a 20-bit (or wider) address into registers, this modifier
  89 selects the 8 bits that would go into CS or ES (i.e. bits 23..16).
  90
  91 @smallexample
  92   mov es, #%hi8(_sym)
  93 @end smallexample
  94
  95 @end table
  96
  97 @node RL78-Directives
  98 @section Assembler Directives
  99
 100 @cindex assembler directives, RL78
 101 @cindex RL78 assembler directives
 102
 103 In addition to the common directives, the RL78 adds these:
 104
 105 @table @code
 106
 107 @item .double
 108 Output a constant in ``double'' format, which is either a 32-bit
 109 or a 64-bit floating point value, depending upon the setting of the
 110 @option{-m32bit-doubles}|@option{-m64bit-doubles} command-line
 111 option.
 112
 113 @item .bss
 114 Select the BSS section.
 115
 116 @item .3byte
 117 Output a constant value in a three byte format.
 118
 119 @item .int
 120 @itemx .word
 121 Output a constant value in a four byte format.
 122
 123 @end table
 124
 125 @node RL78-Syntax
 126 @section Syntax for the RL78
 127 @menu
 128 * RL78-Chars::                Special Characters
 129 @end menu
 130
 131 @node RL78-Chars
 132 @subsection Special Characters
 133
 134 @cindex line comment character, RL78
 135 @cindex RL78 line comment character
 136 The presence of a @samp{;} appearing anywhere on a line indicates the
 137 start of a comment that extends to the end of that line.
 138
 139 If a @samp{#} appears as the first character of a line then the whole
 140 line is treated as a comment, but in this case the line can also be a
 141 logical line number directive (@pxref{Comments}) or a preprocessor
 142 control command (@pxref{Preprocessing}).
 143
 144 @cindex line separator, RL78
 145 @cindex statement separator, RL78
 146 @cindex RL78 line separator
 147 The @samp{|} character can be used to separate statements on the same
 148 line.