xref: /openbmc/linux/arch/powerpc/xmon/ppc-dis.c (revision 6c33a6f4)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* ppc-dis.c -- Disassemble PowerPC instructions
3    Copyright (C) 1994-2016 Free Software Foundation, Inc.
4    Written by Ian Lance Taylor, Cygnus Support
5 
6 This file is part of GDB, GAS, and the GNU binutils.
7 
8  */
9 
10 #include <asm/cputable.h>
11 #include <asm/cpu_has_feature.h>
12 #include "nonstdio.h"
13 #include "ansidecl.h"
14 #include "ppc.h"
15 #include "dis-asm.h"
16 
17 /* This file provides several disassembler functions, all of which use
18    the disassembler interface defined in dis-asm.h.  Several functions
19    are provided because this file handles disassembly for the PowerPC
20    in both big and little endian mode and also for the POWER (RS/6000)
21    chip.  */
22 
23 /* Extract the operand value from the PowerPC or POWER instruction.  */
24 
25 static long
26 operand_value_powerpc (const struct powerpc_operand *operand,
27 		       unsigned long insn, ppc_cpu_t dialect)
28 {
29   long value;
30   int invalid;
31   /* Extract the value from the instruction.  */
32   if (operand->extract)
33     value = (*operand->extract) (insn, dialect, &invalid);
34   else
35     {
36       if (operand->shift >= 0)
37 	value = (insn >> operand->shift) & operand->bitm;
38       else
39 	value = (insn << -operand->shift) & operand->bitm;
40       if ((operand->flags & PPC_OPERAND_SIGNED) != 0)
41 	{
42 	  /* BITM is always some number of zeros followed by some
43 	     number of ones, followed by some number of zeros.  */
44 	  unsigned long top = operand->bitm;
45 	  /* top & -top gives the rightmost 1 bit, so this
46 	     fills in any trailing zeros.  */
47 	  top |= (top & -top) - 1;
48 	  top &= ~(top >> 1);
49 	  value = (value ^ top) - top;
50 	}
51     }
52 
53   return value;
54 }
55 
56 /* Determine whether the optional operand(s) should be printed.  */
57 
58 static int
59 skip_optional_operands (const unsigned char *opindex,
60 			unsigned long insn, ppc_cpu_t dialect)
61 {
62   const struct powerpc_operand *operand;
63 
64   for (; *opindex != 0; opindex++)
65     {
66       operand = &powerpc_operands[*opindex];
67       if ((operand->flags & PPC_OPERAND_NEXT) != 0
68 	  || ((operand->flags & PPC_OPERAND_OPTIONAL) != 0
69 	      && operand_value_powerpc (operand, insn, dialect) !=
70 		 ppc_optional_operand_value (operand)))
71 	return 0;
72     }
73 
74   return 1;
75 }
76 
77 /* Find a match for INSN in the opcode table, given machine DIALECT.
78    A DIALECT of -1 is special, matching all machine opcode variations.  */
79 
80 static const struct powerpc_opcode *
81 lookup_powerpc (unsigned long insn, ppc_cpu_t dialect)
82 {
83   const struct powerpc_opcode *opcode;
84   const struct powerpc_opcode *opcode_end;
85 
86   opcode_end = powerpc_opcodes + powerpc_num_opcodes;
87   /* Find the first match in the opcode table for this major opcode.  */
88   for (opcode = powerpc_opcodes; opcode < opcode_end; ++opcode)
89     {
90       const unsigned char *opindex;
91       const struct powerpc_operand *operand;
92       int invalid;
93 
94       if ((insn & opcode->mask) != opcode->opcode
95 	  || (dialect != (ppc_cpu_t) -1
96 	      && ((opcode->flags & dialect) == 0
97 		  || (opcode->deprecated & dialect) != 0)))
98 	continue;
99 
100       /* Check validity of operands.  */
101       invalid = 0;
102       for (opindex = opcode->operands; *opindex != 0; opindex++)
103 	{
104 	  operand = powerpc_operands + *opindex;
105 	  if (operand->extract)
106 	    (*operand->extract) (insn, dialect, &invalid);
107 	}
108       if (invalid)
109 	continue;
110 
111       return opcode;
112     }
113 
114   return NULL;
115 }
116 
117 /* Print a PowerPC or POWER instruction.  */
118 
119 int print_insn_powerpc (unsigned long insn, unsigned long memaddr)
120 {
121   const struct powerpc_opcode *opcode;
122   bool insn_is_short;
123   ppc_cpu_t dialect;
124 
125   dialect = PPC_OPCODE_PPC | PPC_OPCODE_COMMON
126             | PPC_OPCODE_64 | PPC_OPCODE_POWER4 | PPC_OPCODE_ALTIVEC;
127 
128   if (cpu_has_feature(CPU_FTRS_POWER5))
129     dialect |= PPC_OPCODE_POWER5;
130 
131   if (cpu_has_feature(CPU_FTRS_CELL))
132     dialect |= (PPC_OPCODE_CELL | PPC_OPCODE_ALTIVEC);
133 
134   if (cpu_has_feature(CPU_FTRS_POWER6))
135     dialect |= (PPC_OPCODE_POWER5 | PPC_OPCODE_POWER6 | PPC_OPCODE_ALTIVEC);
136 
137   if (cpu_has_feature(CPU_FTRS_POWER7))
138     dialect |= (PPC_OPCODE_POWER5 | PPC_OPCODE_POWER6 | PPC_OPCODE_POWER7
139                 | PPC_OPCODE_ALTIVEC | PPC_OPCODE_VSX);
140 
141   if (cpu_has_feature(CPU_FTRS_POWER8))
142     dialect |= (PPC_OPCODE_POWER5 | PPC_OPCODE_POWER6 | PPC_OPCODE_POWER7
143 		| PPC_OPCODE_POWER8 | PPC_OPCODE_HTM
144 		| PPC_OPCODE_ALTIVEC | PPC_OPCODE_ALTIVEC2 | PPC_OPCODE_VSX);
145 
146   if (cpu_has_feature(CPU_FTRS_POWER9))
147     dialect |= (PPC_OPCODE_POWER5 | PPC_OPCODE_POWER6 | PPC_OPCODE_POWER7
148 		| PPC_OPCODE_POWER8 | PPC_OPCODE_POWER9 | PPC_OPCODE_HTM
149 		| PPC_OPCODE_ALTIVEC | PPC_OPCODE_ALTIVEC2
150 		| PPC_OPCODE_VSX | PPC_OPCODE_VSX3);
151 
152   /* Get the major opcode of the insn.  */
153   opcode = NULL;
154   insn_is_short = false;
155 
156   if (opcode == NULL)
157     opcode = lookup_powerpc (insn, dialect);
158   if (opcode == NULL && (dialect & PPC_OPCODE_ANY) != 0)
159     opcode = lookup_powerpc (insn, (ppc_cpu_t) -1);
160 
161   if (opcode != NULL)
162     {
163       const unsigned char *opindex;
164       const struct powerpc_operand *operand;
165       int need_comma;
166       int need_paren;
167       int skip_optional;
168 
169       if (opcode->operands[0] != 0)
170 	printf("%-7s ", opcode->name);
171       else
172 	printf("%s", opcode->name);
173 
174       if (insn_is_short)
175         /* The operands will be fetched out of the 16-bit instruction.  */
176         insn >>= 16;
177 
178       /* Now extract and print the operands.  */
179       need_comma = 0;
180       need_paren = 0;
181       skip_optional = -1;
182       for (opindex = opcode->operands; *opindex != 0; opindex++)
183 	{
184 	  long value;
185 
186 	  operand = powerpc_operands + *opindex;
187 
188 	  /* Operands that are marked FAKE are simply ignored.  We
189 	     already made sure that the extract function considered
190 	     the instruction to be valid.  */
191 	  if ((operand->flags & PPC_OPERAND_FAKE) != 0)
192 	    continue;
193 
194 	  /* If all of the optional operands have the value zero,
195 	     then don't print any of them.  */
196 	  if ((operand->flags & PPC_OPERAND_OPTIONAL) != 0)
197 	    {
198 	      if (skip_optional < 0)
199 		skip_optional = skip_optional_operands (opindex, insn,
200 							dialect);
201 	      if (skip_optional)
202 		continue;
203 	    }
204 
205 	  value = operand_value_powerpc (operand, insn, dialect);
206 
207 	  if (need_comma)
208 	    {
209 	      printf(",");
210 	      need_comma = 0;
211 	    }
212 
213 	  /* Print the operand as directed by the flags.  */
214 	  if ((operand->flags & PPC_OPERAND_GPR) != 0
215 	      || ((operand->flags & PPC_OPERAND_GPR_0) != 0 && value != 0))
216 	    printf("r%ld", value);
217 	  else if ((operand->flags & PPC_OPERAND_FPR) != 0)
218 	    printf("f%ld", value);
219 	  else if ((operand->flags & PPC_OPERAND_VR) != 0)
220 	    printf("v%ld", value);
221 	  else if ((operand->flags & PPC_OPERAND_VSR) != 0)
222 	    printf("vs%ld", value);
223 	  else if ((operand->flags & PPC_OPERAND_RELATIVE) != 0)
224 	    print_address(memaddr + value);
225 	  else if ((operand->flags & PPC_OPERAND_ABSOLUTE) != 0)
226 	    print_address(value & 0xffffffff);
227 	  else if ((operand->flags & PPC_OPERAND_FSL) != 0)
228 	    printf("fsl%ld", value);
229 	  else if ((operand->flags & PPC_OPERAND_FCR) != 0)
230 	    printf("fcr%ld", value);
231 	  else if ((operand->flags & PPC_OPERAND_UDI) != 0)
232 	    printf("%ld", value);
233 	  else if ((operand->flags & PPC_OPERAND_CR_REG) != 0
234 		   && (((dialect & PPC_OPCODE_PPC) != 0)
235 		       || ((dialect & PPC_OPCODE_VLE) != 0)))
236 	    printf("cr%ld", value);
237 	  else if (((operand->flags & PPC_OPERAND_CR_BIT) != 0)
238 		   && (((dialect & PPC_OPCODE_PPC) != 0)
239 		       || ((dialect & PPC_OPCODE_VLE) != 0)))
240 	    {
241 	      static const char *cbnames[4] = { "lt", "gt", "eq", "so" };
242 	      int cr;
243 	      int cc;
244 
245 	      cr = value >> 2;
246 	      if (cr != 0)
247 		printf("4*cr%d+", cr);
248 	      cc = value & 3;
249 	      printf("%s", cbnames[cc]);
250 	    }
251 	  else
252 	    printf("%d", (int) value);
253 
254 	  if (need_paren)
255 	    {
256 	      printf(")");
257 	      need_paren = 0;
258 	    }
259 
260 	  if ((operand->flags & PPC_OPERAND_PARENS) == 0)
261 	    need_comma = 1;
262 	  else
263 	    {
264 	      printf("(");
265 	      need_paren = 1;
266 	    }
267 	}
268 
269       /* We have found and printed an instruction.
270          If it was a short VLE instruction we have more to do.  */
271       if (insn_is_short)
272         {
273           memaddr += 2;
274           return 2;
275         }
276       else
277         /* Otherwise, return.  */
278         return 4;
279     }
280 
281   /* We could not find a match.  */
282   printf(".long 0x%lx", insn);
283 
284   return 4;
285 }
286