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-rw-r--r--opcodes/pdp11-dis.c323
1 files changed, 323 insertions, 0 deletions
diff --git a/opcodes/pdp11-dis.c b/opcodes/pdp11-dis.c
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+/* Print DEC PDP-11 instructions.
+ Copyright 2001 Free Software Foundation, Inc.
+
+This file is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+#include "dis-asm.h"
+#include "opcode/pdp11.h"
+
+#define AFTER_INSTRUCTION "\t"
+#define OPERAND_SEPARATOR ", "
+
+#define JUMP 0x1000 /* flag that this operand is used in a jump */
+
+#define FPRINTF (*info->fprintf_func)
+#define F info->stream
+
+/* sign-extend a 16-bit number in an int */
+#define SIGN_BITS (8 * sizeof (int) - 16)
+#define sign_extend(x) (((x) << SIGN_BITS) >> SIGN_BITS)
+
+static int read_word PARAMS ((bfd_vma memaddr, int *word,
+ disassemble_info *info));
+static void print_signed_octal PARAMS ((int n, disassemble_info *info));
+static void print_reg PARAMS ((int reg, disassemble_info *info));
+static void print_freg PARAMS ((int freg, disassemble_info *info));
+static int print_operand PARAMS ((bfd_vma *memaddr, int code,
+ disassemble_info *info));
+int print_insn_pdp11 PARAMS ((bfd_vma memaddr, disassemble_info *info));
+
+static int
+read_word (memaddr, word, info)
+ bfd_vma memaddr;
+ int *word;
+ disassemble_info *info;
+{
+ int status;
+ bfd_byte x[2];
+
+ status = (*info->read_memory_func) (memaddr, x, 2, info);
+ if (status != 0)
+ return -1;
+
+ *word = x[1] << 8 | x[0];
+ return 0;
+}
+
+static void
+print_signed_octal (n, info)
+ int n;
+ disassemble_info *info;
+{
+ if (n < 0)
+ FPRINTF (F, "-%o", -n);
+ else
+ FPRINTF (F, "%o", n);
+}
+
+static void
+print_reg (reg, info)
+ int reg;
+ disassemble_info *info;
+{
+ /* mask off the addressing mode, if any */
+ reg &= 7;
+
+ switch (reg)
+ {
+ case 0: case 1: case 2: case 3: case 4: case 5:
+ FPRINTF (F, "r%d", reg); break;
+ case 6: FPRINTF (F, "sp"); break;
+ case 7: FPRINTF (F, "pc"); break;
+ default: /* error */
+ }
+}
+
+static void
+print_freg (freg, info)
+ int freg;
+ disassemble_info *info;
+{
+ FPRINTF (F, "fr%d", freg);
+}
+
+static int
+print_operand (memaddr, code, info)
+ bfd_vma *memaddr;
+ int code;
+ disassemble_info *info;
+{
+ int mode = (code >> 3) & 7;
+ int reg = code & 7;
+ int disp;
+
+ switch (mode)
+ {
+ case 0:
+ print_reg (reg, info);
+ break;
+ case 1:
+ FPRINTF (F, "(");
+ print_reg (reg, info);
+ FPRINTF (F, ")");
+ break;
+ case 2:
+ if (reg == 7)
+ {
+ int data;
+ if (read_word (*memaddr, &data, info) < 0)
+ return -1;
+ FPRINTF (F, "$");
+ print_signed_octal (sign_extend (data), info);
+ *memaddr += 2;
+ }
+ else
+ {
+ FPRINTF (F, "(");
+ print_reg (reg, info);
+ FPRINTF (F, ")+");
+ }
+ break;
+ case 3:
+ if (reg == 7)
+ {
+ int address;
+ if (read_word (*memaddr, &address, info) < 0)
+ return -1;
+ FPRINTF (F, "*$%o", address);
+ *memaddr += 2;
+ }
+ else
+ {
+ FPRINTF (F, "*(");
+ print_reg (reg, info);
+ FPRINTF (F, ")+");
+ }
+ break;
+ case 4:
+ FPRINTF (F, "-(");
+ print_reg (reg, info);
+ FPRINTF (F, ")");
+ break;
+ case 5:
+ FPRINTF (F, "*-(");
+ print_reg (reg, info);
+ FPRINTF (F, ")");
+ break;
+ case 6:
+ case 7:
+ if (read_word (*memaddr, &disp, info) < 0)
+ return -1;
+ *memaddr += 2;
+ if (reg == 7)
+ {
+ bfd_vma address = *memaddr + sign_extend (disp);
+ if (!(code & JUMP))
+ FPRINTF (F, "*$");
+ (*info->print_address_func) (address, info);
+ }
+ else
+ {
+ if (mode == 7)
+ FPRINTF (F, "*");
+ print_signed_octal (sign_extend (disp), info);
+ FPRINTF (F, "(");
+ print_reg (reg, info);
+ FPRINTF (F, ")");
+ }
+ break;
+ }
+
+ return 0;
+}
+
+/* Print the PDP-11 instruction at address MEMADDR in debugged memory,
+ on INFO->STREAM. Returns length of the instruction, in bytes. */
+
+int
+print_insn_pdp11 (memaddr, info)
+ bfd_vma memaddr;
+ disassemble_info *info;
+{
+ bfd_vma start_memaddr = memaddr;
+ int opcode;
+ int src, dst;
+ int i;
+
+ info->bytes_per_line = 6;
+ info->bytes_per_chunk = 2;
+ info->display_endian = BFD_ENDIAN_LITTLE;
+
+ if (read_word (memaddr, &opcode, info) != 0)
+ return -1;
+ memaddr += 2;
+
+ src = (opcode >> 6) & 0x3f;
+ dst = opcode & 0x3f;
+
+ for (i = 0; i < pdp11_num_opcodes; i++)
+ {
+#define OP pdp11_opcodes[i]
+ if ((opcode & OP.mask) == OP.opcode)
+ switch (OP.type)
+ {
+ case PDP11_OPCODE_NO_OPS:
+ FPRINTF (F, OP.name);
+ break;
+ case PDP11_OPCODE_REG:
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ print_reg (dst, info);
+ break;
+ case PDP11_OPCODE_OP:
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ if (strcmp (OP.name, "jmp") == 0)
+ dst |= JUMP;
+ if (print_operand (&memaddr, dst, info) < 0)
+ return -1;
+ break;
+ case PDP11_OPCODE_REG_OP:
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ print_reg (src, info);
+ FPRINTF (F, OPERAND_SEPARATOR);
+ if (strcmp (OP.name, "jsr") == 0)
+ dst |= JUMP;
+ if (print_operand (&memaddr, dst, info) < 0)
+ return -1;
+ break;
+ case PDP11_OPCODE_REG_OP_REV:
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ if (print_operand (&memaddr, dst, info) < 0)
+ return -1;
+ FPRINTF (F, OPERAND_SEPARATOR);
+ print_reg (src, info);
+ break;
+ case PDP11_OPCODE_AC_OP:
+ {
+ int ac = (opcode & 0xe0) >> 6;
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ print_freg (ac, info);
+ FPRINTF (F, OPERAND_SEPARATOR);
+ if (print_operand (&memaddr, dst, info) < 0)
+ return -1;
+ break;
+ }
+ case PDP11_OPCODE_OP_OP:
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ if (print_operand (&memaddr, src, info) < 0)
+ return -1;
+ FPRINTF (F, OPERAND_SEPARATOR);
+ if (print_operand (&memaddr, dst, info) < 0)
+ return -1;
+ break;
+ case PDP11_OPCODE_DISPL:
+ {
+ int displ = (opcode & 0xff) << 8;
+ bfd_vma address = memaddr + (sign_extend (displ) >> 7);
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ (*info->print_address_func) (address, info);
+ break;
+ }
+ case PDP11_OPCODE_REG_DISPL:
+ {
+ int displ = (opcode & 0x3f) << 10;
+ bfd_vma address = memaddr + (sign_extend (displ) >> 9);
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ print_reg (src, info);
+ FPRINTF (F, OPERAND_SEPARATOR);
+ (*info->print_address_func) (address, info);
+ break;
+ }
+ case PDP11_OPCODE_IMM8:
+ {
+ int code = opcode & 0xff;
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ FPRINTF (F, "%o", code);
+ break;
+ }
+ case PDP11_OPCODE_IMM6:
+ {
+ int code = opcode & 0x3f;
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ FPRINTF (F, "%o", code);
+ break;
+ }
+ case PDP11_OPCODE_IMM3:
+ {
+ int code = opcode & 7;
+ FPRINTF (F, OP.name);
+ FPRINTF (F, AFTER_INSTRUCTION);
+ FPRINTF (F, "%o", code);
+ break;
+ }
+ default:
+ /* TODO: is this a proper way of signalling an error? */
+ FPRINTF (F, "<internal error: unrecognized instruction type>");
+ return -1;
+ }
+#undef OP
+ }
+
+ return memaddr - start_memaddr;
+}
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