328 lines
10 KiB
C
328 lines
10 KiB
C
/* Target-dependent code for PowerPC systems using the SVR4 ABI
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for GDB, the GNU debugger.
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Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "gdbcore.h"
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#include "inferior.h"
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#include "regcache.h"
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#include "value.h"
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#include "gdb_string.h"
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#include "ppc-tdep.h"
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/* Pass the arguments in either registers, or in the stack. Using the
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ppc sysv ABI, the first eight words of the argument list (that might
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be less than eight parameters if some parameters occupy more than one
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word) are passed in r3..r10 registers. float and double parameters are
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passed in fpr's, in addition to that. Rest of the parameters if any
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are passed in user stack.
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If the function is returning a structure, then the return address is passed
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in r3, then the first 7 words of the parametes can be passed in registers,
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starting from r4. */
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CORE_ADDR
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ppc_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, CORE_ADDR func_addr,
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struct regcache *regcache, CORE_ADDR bp_addr,
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int nargs, struct value **args, CORE_ADDR sp,
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int struct_return, CORE_ADDR struct_addr)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
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const CORE_ADDR saved_sp = read_sp ();
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int argspace = 0; /* 0 is an initial wrong guess. */
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int write_pass;
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/* Go through the argument list twice.
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Pass 1: Figure out how much new stack space is required for
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arguments and pushed values. Unlike the PowerOpen ABI, the SysV
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ABI doesn't reserve any extra space for parameters which are put
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in registers, but does always push structures and then pass their
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address.
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Pass 2: Replay the same computation but this time also write the
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values out to the target. */
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for (write_pass = 0; write_pass < 2; write_pass++)
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{
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int argno;
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/* Next available floating point register for float and double
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arguments. */
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int freg = 1;
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/* Next available general register for non-float, non-vector
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arguments. */
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int greg = 3;
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/* Next available vector register for vector arguments. */
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int vreg = 2;
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/* Arguments start above the "LR save word" and "Back chain". */
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int argoffset = 2 * tdep->wordsize;
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/* Structures start after the arguments. */
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int structoffset = argoffset + argspace;
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/* If the function is returning a `struct', then the first word
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(which will be passed in r3) is used for struct return
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address. In that case we should advance one word and start
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from r4 register to copy parameters. */
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if (struct_return)
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{
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if (write_pass)
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regcache_cooked_write_signed (regcache,
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tdep->ppc_gp0_regnum + greg,
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struct_addr);
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greg++;
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}
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for (argno = 0; argno < nargs; argno++)
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{
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struct value *arg = args[argno];
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struct type *type = check_typedef (VALUE_TYPE (arg));
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int len = TYPE_LENGTH (type);
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char *val = VALUE_CONTENTS (arg);
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if (TYPE_CODE (type) == TYPE_CODE_FLT
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&& ppc_floating_point_unit_p (current_gdbarch)
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&& len <= 8)
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{
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/* Floating point value converted to "double" then
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passed in an FP register, when the registers run out,
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8 byte aligned stack is used. */
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if (freg <= 8)
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{
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if (write_pass)
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{
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/* Always store the floating point value using
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the register's floating-point format. */
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char regval[MAX_REGISTER_SIZE];
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struct type *regtype
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= register_type (gdbarch, FP0_REGNUM + freg);
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convert_typed_floating (val, type, regval, regtype);
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regcache_cooked_write (regcache, FP0_REGNUM + freg,
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regval);
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}
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freg++;
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}
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else
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{
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/* SysV ABI converts floats to doubles before
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writing them to an 8 byte aligned stack location. */
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argoffset = align_up (argoffset, 8);
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if (write_pass)
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{
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char memval[8];
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struct type *memtype;
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switch (TARGET_BYTE_ORDER)
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{
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case BFD_ENDIAN_BIG:
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memtype = builtin_type_ieee_double_big;
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break;
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case BFD_ENDIAN_LITTLE:
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memtype = builtin_type_ieee_double_little;
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break;
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default:
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internal_error (__FILE__, __LINE__, "bad switch");
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}
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convert_typed_floating (val, type, memval, memtype);
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write_memory (sp + argoffset, val, len);
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}
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argoffset += 8;
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}
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}
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else if (len == 8
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&& (TYPE_CODE (type) == TYPE_CODE_INT /* long long */
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|| (!ppc_floating_point_unit_p (current_gdbarch)
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&& TYPE_CODE (type) == TYPE_CODE_FLT))) /* double */
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{
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/* "long long" or "double" passed in an odd/even
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register pair with the low addressed word in the odd
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register and the high addressed word in the even
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register, or when the registers run out an 8 byte
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aligned stack location. */
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if (greg > 9)
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{
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/* Just in case GREG was 10. */
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greg = 11;
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argoffset = align_up (argoffset, 8);
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if (write_pass)
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write_memory (sp + argoffset, val, len);
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argoffset += 8;
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}
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else if (tdep->wordsize == 8)
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{
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if (write_pass)
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regcache_cooked_write (regcache,
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tdep->ppc_gp0_regnum + greg,
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val);
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greg += 1;
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}
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else
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{
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/* Must start on an odd register - r3/r4 etc. */
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if ((greg & 1) == 0)
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greg++;
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if (write_pass)
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{
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regcache_cooked_write (regcache,
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tdep->ppc_gp0_regnum + greg + 0,
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val + 0);
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regcache_cooked_write (regcache,
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tdep->ppc_gp0_regnum + greg + 1,
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val + 4);
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}
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greg += 2;
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}
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}
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else if (len == 16
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&& TYPE_CODE (type) == TYPE_CODE_ARRAY
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&& TYPE_VECTOR (type)
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&& tdep->ppc_vr0_regnum >= 0)
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{
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/* Vector parameter passed in an Altivec register, or
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when that runs out, 16 byte aligned stack location. */
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if (vreg <= 13)
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{
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if (write_pass)
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regcache_cooked_write (current_regcache,
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tdep->ppc_vr0_regnum + vreg,
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val);
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vreg++;
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}
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else
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{
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argoffset = align_up (argoffset, 16);
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if (write_pass)
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write_memory (sp + argoffset, val, 16);
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argoffset += 16;
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}
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}
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else if (len == 8
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&& TYPE_CODE (type) == TYPE_CODE_ARRAY
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&& TYPE_VECTOR (type)
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&& tdep->ppc_ev0_regnum >= 0)
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{
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/* Vector parameter passed in an e500 register, or when
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that runs out, 8 byte aligned stack location. Note
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that since e500 vector and general purpose registers
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both map onto the same underlying register set, a
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"greg" and not a "vreg" is consumed here. A cooked
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write stores the value in the correct locations
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within the raw register cache. */
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if (greg <= 10)
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{
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if (write_pass)
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regcache_cooked_write (current_regcache,
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tdep->ppc_ev0_regnum + greg,
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val);
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greg++;
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}
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else
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{
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argoffset = align_up (argoffset, 8);
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if (write_pass)
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write_memory (sp + argoffset, val, 8);
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argoffset += 8;
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}
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}
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else
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{
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/* Reduce the parameter down to something that fits in a
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"word". */
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char word[MAX_REGISTER_SIZE];
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memset (word, 0, MAX_REGISTER_SIZE);
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if (len > tdep->wordsize
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|| TYPE_CODE (type) == TYPE_CODE_STRUCT
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|| TYPE_CODE (type) == TYPE_CODE_UNION)
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{
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/* Structs and large values are put on an 8 byte
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aligned stack ... */
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structoffset = align_up (structoffset, 8);
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if (write_pass)
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write_memory (sp + structoffset, val, len);
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/* ... and then a "word" pointing to that address is
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passed as the parameter. */
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store_unsigned_integer (word, tdep->wordsize,
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sp + structoffset);
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structoffset += len;
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}
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else if (TYPE_CODE (type) == TYPE_CODE_INT)
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/* Sign or zero extend the "int" into a "word". */
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store_unsigned_integer (word, tdep->wordsize,
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unpack_long (type, val));
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else
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/* Always goes in the low address. */
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memcpy (word, val, len);
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/* Store that "word" in a register, or on the stack.
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The words have "4" byte alignment. */
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if (greg <= 10)
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{
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if (write_pass)
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regcache_cooked_write (regcache,
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tdep->ppc_gp0_regnum + greg,
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word);
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greg++;
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}
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else
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{
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argoffset = align_up (argoffset, tdep->wordsize);
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if (write_pass)
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write_memory (sp + argoffset, word, tdep->wordsize);
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argoffset += tdep->wordsize;
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}
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}
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}
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/* Compute the actual stack space requirements. */
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if (!write_pass)
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{
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/* Remember the amount of space needed by the arguments. */
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argspace = argoffset;
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/* Allocate space for both the arguments and the structures. */
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sp -= (argoffset + structoffset);
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/* Ensure that the stack is still 16 byte aligned. */
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sp = align_down (sp, 16);
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}
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}
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/* Update %sp. */
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regcache_cooked_write_signed (regcache, SP_REGNUM, sp);
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/* Write the backchain (it occupies WORDSIZED bytes). */
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write_memory_signed_integer (sp, tdep->wordsize, saved_sp);
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/* Point the inferior function call's return address at the dummy's
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breakpoint. */
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regcache_cooked_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr);
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return sp;
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}
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/* Structures 8 bytes or less long are returned in the r3 & r4
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registers, according to the SYSV ABI. */
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int
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ppc_sysv_abi_use_struct_convention (int gcc_p, struct type *value_type)
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{
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if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8)
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&& TYPE_VECTOR (value_type))
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return 0;
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return (TYPE_LENGTH (value_type) > 8);
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}
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