1 @c Copyright (C) 2008-2014 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 LM32-Dependent 8 @chapter LM32 Dependent Features 9 @end ifset 10 11 @ifclear GENERIC 12 @node Machine Dependencies 13 @chapter LM" Dependent Features 14 @end ifclear 15 16 @cindex LM32 support 17 @menu 18 * LM32 Options:: Options 19 * LM32 Syntax:: Syntax 20 * LM32 Opcodes:: Opcodes 21 @end menu 22 23 @node LM32 Options 24 @section Options 25 @cindex LM32 options (none) 26 @cindex options for LM32 (none) 27 28 @table @code 29 30 @cindex @code{-mmultiply-enabled} command line option, LM32 31 @item -mmultiply-enabled 32 Enable multiply instructions. 33 34 @cindex @code{-mdivide-enabled} command line option, LM32 35 @item -mdivide-enabled 36 Enable divide instructions. 37 38 @cindex @code{-mbarrel-shift-enabled} command line option, LM32 39 @item -mbarrel-shift-enabled 40 Enable barrel-shift instructions. 41 42 @cindex @code{-msign-extend-enabled} command line option, LM32 43 @item -msign-extend-enabled 44 Enable sign extend instructions. 45 46 @cindex @code{-muser-enabled} command line option, LM32 47 @item -muser-enabled 48 Enable user defined instructions. 49 50 @cindex @code{-micache-enabled} command line option, LM32 51 @item -micache-enabled 52 Enable instruction cache related CSRs. 53 54 @cindex @code{-mdcache-enabled} command line option, LM32 55 @item -mdcache-enabled 56 Enable data cache related CSRs. 57 58 @cindex @code{-mbreak-enabled} command line option, LM32 59 @item -mbreak-enabled 60 Enable break instructions. 61 62 @cindex @code{-mall-enabled} command line option, LM32 63 @item -mall-enabled 64 Enable all instructions and CSRs. 65 66 @end table 67 68 69 @node LM32 Syntax 70 @section Syntax 71 @menu 72 * LM32-Regs:: Register Names 73 * LM32-Modifiers:: Relocatable Expression Modifiers 74 * LM32-Chars:: Special Characters 75 @end menu 76 77 @node LM32-Regs 78 @subsection Register Names 79 80 @cindex LM32 register names 81 @cindex register names, LM32 82 83 LM32 has 32 x 32-bit general purpose registers @samp{r0}, 84 @samp{r1}, ... @samp{r31}. 85 86 The following aliases are defined: @samp{gp} - @samp{r26}, 87 @samp{fp} - @samp{r27}, @samp{sp} - @samp{r28}, 88 @samp{ra} - @samp{r29}, @samp{ea} - @samp{r30}, 89 @samp{ba} - @samp{r31}. 90 91 LM32 has the following Control and Status Registers (CSRs). 92 93 @table @code 94 @item IE 95 Interrupt enable. 96 @item IM 97 Interrupt mask. 98 @item IP 99 Interrupt pending. 100 @item ICC 101 Instruction cache control. 102 @item DCC 103 Data cache control. 104 @item CC 105 Cycle counter. 106 @item CFG 107 Configuration. 108 @item EBA 109 Exception base address. 110 @item DC 111 Debug control. 112 @item DEBA 113 Debug exception base address. 114 @item JTX 115 JTAG transmit. 116 @item JRX 117 JTAG receive. 118 @item BP0 119 Breakpoint 0. 120 @item BP1 121 Breakpoint 1. 122 @item BP2 123 Breakpoint 2. 124 @item BP3 125 Breakpoint 3. 126 @item WP0 127 Watchpoint 0. 128 @item WP1 129 Watchpoint 1. 130 @item WP2 131 Watchpoint 2. 132 @item WP3 133 Watchpoint 3. 134 @end table 135 136 @node LM32-Modifiers 137 @subsection Relocatable Expression Modifiers 138 139 @cindex LM32 modifiers 140 @cindex syntax, LM32 141 142 The assembler supports several modifiers when using relocatable addresses 143 in LM32 instruction operands. The general syntax is the following: 144 145 @smallexample 146 modifier(relocatable-expression) 147 @end smallexample 148 149 @table @code 150 @cindex symbol modifiers 151 152 @item lo 153 154 This modifier allows you to use bits 0 through 15 of 155 an address expression as 16 bit relocatable expression. 156 157 @item hi 158 159 This modifier allows you to use bits 16 through 23 of an address expression 160 as 16 bit relocatable expression. 161 162 For example 163 164 @smallexample 165 ori r4, r4, lo(sym+10) 166 orhi r4, r4, hi(sym+10) 167 @end smallexample 168 169 @item gp 170 171 This modified creates a 16-bit relocatable expression that is 172 the offset of the symbol from the global pointer. 173 174 @smallexample 175 mva r4, gp(sym) 176 @end smallexample 177 178 @item got 179 180 This modifier places a symbol in the GOT and creates a 16-bit 181 relocatable expression that is the offset into the GOT of this 182 symbol. 183 184 @smallexample 185 lw r4, (gp+got(sym)) 186 @end smallexample 187 188 @item gotofflo16 189 190 This modifier allows you to use the bits 0 through 15 of an 191 address which is an offset from the GOT. 192 193 @item gotoffhi16 194 195 This modifier allows you to use the bits 16 through 31 of an 196 address which is an offset from the GOT. 197 198 @smallexample 199 orhi r4, r4, gotoffhi16(lsym) 200 addi r4, r4, gotofflo16(lsym) 201 @end smallexample 202 203 @end table 204 205 @node LM32-Chars 206 @subsection Special Characters 207 208 @cindex line comment character, LM32 209 @cindex LM32 line comment character 210 The presence of a @samp{#} on a line indicates the start of a comment 211 that extends to the end of the current line. Note that if a line 212 starts with a @samp{#} character then it can also be a logical line 213 number directive (@pxref{Comments}) or a preprocessor 214 control command (@pxref{Preprocessing}). 215 216 @cindex line separator, LM32 217 @cindex statement separator, LM32 218 @cindex LM32 line separator 219 A semicolon (@samp{;}) can be used to separate multiple statements on 220 the same line. 221 222 @node LM32 Opcodes 223 @section Opcodes 224 225 @cindex LM32 opcode summary 226 @cindex opcode summary, LM32 227 @cindex mnemonics, LM32 228 @cindex instruction summary, LM32 229 For detailed information on the LM32 machine instruction set, see 230 @url{http://www.latticesemi.com/products/intellectualproperty/ipcores/mico32/}. 231 232 @code{@value{AS}} implements all the standard LM32 opcodes. 233
