+/* When arguments must be pushed onto the stack, they go on in reverse
+ order. The code below implements a FILO (stack) to do this. */
+
+struct stack_item
+{
+ int len;
+ struct stack_item *prev;
+ void *data;
+};
+
+static struct stack_item *
+push_stack_item (struct stack_item *prev, void *contents, int len)
+{
+ struct stack_item *si;
+ si = xmalloc (sizeof (struct stack_item));
+ si->data = xmalloc (len);
+ si->len = len;
+ si->prev = prev;
+ memcpy (si->data, contents, len);
+ return si;
+}
+
+static struct stack_item *
+pop_stack_item (struct stack_item *si)
+{
+ struct stack_item *dead = si;
+ si = si->prev;
+ xfree (dead->data);
+ xfree (dead);
+ return si;
+}
+
+/* We currently only support passing parameters in integer registers. This
+ conforms with GCC's default model. Several other variants exist and
+ we should probably support some of them based on the selected ABI. */
+
+static CORE_ADDR
+arm_push_dummy_call (struct gdbarch *gdbarch, struct regcache *regcache,
+ CORE_ADDR dummy_addr, int nargs, struct value **args,
+ CORE_ADDR sp, int struct_return, CORE_ADDR struct_addr)
+{
+ int argnum;
+ int argreg;
+ int nstack;
+ struct stack_item *si = NULL;
+
+ /* Set the return address. For the ARM, the return breakpoint is always
+ at DUMMY_ADDR. */
+ /* XXX Fix for Thumb. */
+ regcache_cooked_write_unsigned (regcache, ARM_LR_REGNUM, dummy_addr);
+
+ /* Walk through the list of args and determine how large a temporary
+ stack is required. Need to take care here as structs may be
+ passed on the stack, and we have to to push them. */
+ nstack = 0;
+
+ argreg = ARM_A1_REGNUM;
+ nstack = 0;
+
+ /* Some platforms require a double-word aligned stack. Make sure sp
+ is correctly aligned before we start. We always do this even if
+ it isn't really needed -- it can never hurt things. */
+ sp &= ~(CORE_ADDR)(2 * REGISTER_SIZE - 1);
+
+ /* The struct_return pointer occupies the first parameter
+ passing register. */
+ if (struct_return)
+ {
+ if (arm_debug)
+ fprintf_unfiltered (gdb_stdlog, "struct return in %s = 0x%s\n",
+ REGISTER_NAME (argreg), paddr (struct_addr));
+ regcache_cooked_write_unsigned (regcache, argreg, struct_addr);
+ argreg++;
+ }
+
+ for (argnum = 0; argnum < nargs; argnum++)
+ {
+ int len;
+ struct type *arg_type;
+ struct type *target_type;
+ enum type_code typecode;
+ char *val;
+
+ arg_type = check_typedef (VALUE_TYPE (args[argnum]));
+ len = TYPE_LENGTH (arg_type);
+ target_type = TYPE_TARGET_TYPE (arg_type);
+ typecode = TYPE_CODE (arg_type);
+ val = VALUE_CONTENTS (args[argnum]);
+
+ /* If the argument is a pointer to a function, and it is a
+ Thumb function, create a LOCAL copy of the value and set
+ the THUMB bit in it. */
+ if (TYPE_CODE_PTR == typecode
+ && target_type != NULL
+ && TYPE_CODE_FUNC == TYPE_CODE (target_type))
+ {
+ CORE_ADDR regval = extract_address (val, len);
+ if (arm_pc_is_thumb (regval))
+ {
+ val = alloca (len);
+ store_address (val, len, MAKE_THUMB_ADDR (regval));
+ }
+ }
+
+ /* Copy the argument to general registers or the stack in
+ register-sized pieces. Large arguments are split between
+ registers and stack. */
+ while (len > 0)
+ {
+ int partial_len = len < REGISTER_SIZE ? len : REGISTER_SIZE;
+
+ if (argreg <= ARM_LAST_ARG_REGNUM)
+ {
+ /* The argument is being passed in a general purpose
+ register. */
+ CORE_ADDR regval = extract_address (val, partial_len);
+ if (arm_debug)
+ fprintf_unfiltered (gdb_stdlog, "arg %d in %s = 0x%s\n",
+ argnum, REGISTER_NAME (argreg),
+ phex (regval, REGISTER_SIZE));
+ regcache_cooked_write_unsigned (regcache, argreg, regval);
+ argreg++;
+ }
+ else
+ {
+ /* Push the arguments onto the stack. */
+ if (arm_debug)
+ fprintf_unfiltered (gdb_stdlog, "arg %d @ sp + %d\n",
+ argnum, nstack);
+ si = push_stack_item (si, val, REGISTER_SIZE);
+ nstack += REGISTER_SIZE;
+ }
+
+ len -= partial_len;
+ val += partial_len;
+ }
+ }
+ /* If we have an odd number of words to push, then decrement the stack
+ by one word now, so first stack argument will be dword aligned. */
+ if (nstack & 4)
+ sp -= 4;
+
+ while (si)
+ {
+ sp -= si->len;
+ write_memory (sp, si->data, si->len);
+ si = pop_stack_item (si);
+ }
+
+ /* Finally, update teh SP register. */
+ regcache_cooked_write_unsigned (regcache, ARM_SP_REGNUM, sp);
+
+ return sp;
+}
+