+/* Extract the operand value from the PowerPC or POWER instruction. */
+
+static long
+operand_value_powerpc (const struct powerpc_operand *operand,
+ unsigned long insn, ppc_cpu_t dialect)
+{
+ long value;
+ int invalid;
+ /* Extract the value from the instruction. */
+ if (operand->extract)
+ value = (*operand->extract) (insn, dialect, &invalid);
+ else
+ {
+ value = (insn >> operand->shift) & operand->bitm;
+ if ((operand->flags & PPC_OPERAND_SIGNED) != 0)
+ {
+ /* BITM is always some number of zeros followed by some
+ number of ones, followed by some numer of zeros. */
+ unsigned long top = operand->bitm;
+ /* top & -top gives the rightmost 1 bit, so this
+ fills in any trailing zeros. */
+ top |= (top & -top) - 1;
+ top &= ~(top >> 1);
+ value = (value ^ top) - top;
+ }
+ }
+
+ return value;
+}
+
+/* Determine whether the optional operand(s) should be printed. */
+
+static int
+skip_optional_operands (const unsigned char *opindex,
+ unsigned long insn, ppc_cpu_t dialect)
+{
+ const struct powerpc_operand *operand;
+
+ for (; *opindex != 0; opindex++)
+ {
+ operand = &powerpc_operands[*opindex];
+ if ((operand->flags & PPC_OPERAND_NEXT) != 0
+ || ((operand->flags & PPC_OPERAND_OPTIONAL) != 0
+ && operand_value_powerpc (operand, insn, dialect) != 0))
+ return 0;
+ }
+
+ return 1;
+}
+