| /* Target-dependent code for PowerPC systems using the SVR4 ABI |
| for GDB, the GNU debugger. |
| |
| Copyright 2000, 2001, 2002 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program 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 "defs.h" |
| #include "gdbcore.h" |
| #include "inferior.h" |
| #include "regcache.h" |
| #include "value.h" |
| #include "gdb_string.h" |
| |
| #include "ppc-tdep.h" |
| |
| /* Ensure that X is aligned to an S byte boundary (assuming that S is |
| a power of 2) rounding up/down where necessary. */ |
| |
| static ULONGEST |
| align_up (ULONGEST x, int s) |
| { |
| return (x + s - 1) & -s; |
| } |
| |
| static ULONGEST |
| align_down (ULONGEST x, int s) |
| { |
| return (x & -s); |
| } |
| |
| /* Pass the arguments in either registers, or in the stack. Using the |
| ppc sysv ABI, the first eight words of the argument list (that might |
| be less than eight parameters if some parameters occupy more than one |
| word) are passed in r3..r10 registers. float and double parameters are |
| passed in fpr's, in addition to that. Rest of the parameters if any |
| are passed in user stack. |
| |
| If the function is returning a structure, then the return address is passed |
| in r3, then the first 7 words of the parametes can be passed in registers, |
| starting from r4. */ |
| |
| CORE_ADDR |
| ppc_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, CORE_ADDR func_addr, |
| struct regcache *regcache, CORE_ADDR bp_addr, |
| int nargs, struct value **args, CORE_ADDR sp, |
| int struct_return, CORE_ADDR struct_addr) |
| { |
| struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); |
| const CORE_ADDR saved_sp = read_sp (); |
| int argspace = 0; /* 0 is an initial wrong guess. */ |
| int write_pass; |
| |
| /* Go through the argument list twice. |
| |
| Pass 1: Figure out how much new stack space is required for |
| arguments and pushed values. Unlike the PowerOpen ABI, the SysV |
| ABI doesn't reserve any extra space for parameters which are put |
| in registers, but does always push structures and then pass their |
| address. |
| |
| Pass 2: Replay the same computation but this time also write the |
| values out to the target. */ |
| |
| for (write_pass = 0; write_pass < 2; write_pass++) |
| { |
| int argno; |
| /* Next available floating point register for float and double |
| arguments. */ |
| int freg = 1; |
| /* Next available general register for non-float, non-vector |
| arguments. */ |
| int greg = 3; |
| /* Next available vector register for vector arguments. */ |
| int vreg = 2; |
| /* Arguments start above the "LR save word" and "Back chain". */ |
| int argoffset = 2 * tdep->wordsize; |
| /* Structures start after the arguments. */ |
| int structoffset = argoffset + argspace; |
| |
| /* If the function is returning a `struct', then the first word |
| (which will be passed in r3) is used for struct return |
| address. In that case we should advance one word and start |
| from r4 register to copy parameters. */ |
| if (struct_return) |
| { |
| if (write_pass) |
| regcache_cooked_write_signed (regcache, |
| tdep->ppc_gp0_regnum + greg, |
| struct_addr); |
| greg++; |
| } |
| |
| for (argno = 0; argno < nargs; argno++) |
| { |
| struct value *arg = args[argno]; |
| struct type *type = check_typedef (VALUE_TYPE (arg)); |
| int len = TYPE_LENGTH (type); |
| char *val = VALUE_CONTENTS (arg); |
| |
| if (TYPE_CODE (type) == TYPE_CODE_FLT |
| && ppc_floating_point_unit_p (current_gdbarch) |
| && len <= 8) |
| { |
| /* Floating point value converted to "double" then |
| passed in an FP register, when the registers run out, |
| 8 byte aligned stack is used. */ |
| if (freg <= 8) |
| { |
| if (write_pass) |
| { |
| /* Always store the floating point value using |
| the register's floating-point format. */ |
| char regval[MAX_REGISTER_SIZE]; |
| struct type *regtype |
| = register_type (gdbarch, FP0_REGNUM + freg); |
| convert_typed_floating (val, type, regval, regtype); |
| regcache_cooked_write (regcache, FP0_REGNUM + freg, |
| regval); |
| } |
| freg++; |
| } |
| else |
| { |
| /* SysV ABI converts floats to doubles before |
| writing them to an 8 byte aligned stack location. */ |
| argoffset = align_up (argoffset, 8); |
| if (write_pass) |
| { |
| char memval[8]; |
| struct type *memtype; |
| switch (TARGET_BYTE_ORDER) |
| { |
| case BFD_ENDIAN_BIG: |
| memtype = builtin_type_ieee_double_big; |
| break; |
| case BFD_ENDIAN_LITTLE: |
| memtype = builtin_type_ieee_double_little; |
| break; |
| default: |
| internal_error (__FILE__, __LINE__, "bad switch"); |
| } |
| convert_typed_floating (val, type, memval, memtype); |
| write_memory (sp + argoffset, val, len); |
| } |
| argoffset += 8; |
| } |
| } |
| else if (len == 8 |
| && (TYPE_CODE (type) == TYPE_CODE_INT /* long long */ |
| || (!ppc_floating_point_unit_p (current_gdbarch) |
| && TYPE_CODE (type) == TYPE_CODE_FLT))) /* double */ |
| { |
| /* "long long" or "double" passed in an odd/even |
| register pair with the low addressed word in the odd |
| register and the high addressed word in the even |
| register, or when the registers run out an 8 byte |
| aligned stack location. */ |
| if (greg > 9) |
| { |
| /* Just in case GREG was 10. */ |
| greg = 11; |
| argoffset = align_up (argoffset, 8); |
| if (write_pass) |
| write_memory (sp + argoffset, val, len); |
| argoffset += 8; |
| } |
| else if (tdep->wordsize == 8) |
| { |
| if (write_pass) |
| regcache_cooked_write (regcache, |
| tdep->ppc_gp0_regnum + greg, |
| val); |
| greg += 1; |
| } |
| else |
| { |
| /* Must start on an odd register - r3/r4 etc. */ |
| if ((greg & 1) == 0) |
| greg++; |
| if (write_pass) |
| { |
| regcache_cooked_write (regcache, |
| tdep->ppc_gp0_regnum + greg + 0, |
| val + 0); |
| regcache_cooked_write (regcache, |
| tdep->ppc_gp0_regnum + greg + 1, |
| val + 4); |
| } |
| greg += 2; |
| } |
| } |
| else if (len == 16 |
| && TYPE_CODE (type) == TYPE_CODE_ARRAY |
| && TYPE_VECTOR (type) |
| && tdep->ppc_vr0_regnum >= 0) |
| { |
| /* Vector parameter passed in an Altivec register, or |
| when that runs out, 16 byte aligned stack location. */ |
| if (vreg <= 13) |
| { |
| if (write_pass) |
| regcache_cooked_write (current_regcache, |
| tdep->ppc_vr0_regnum + vreg, |
| val); |
| vreg++; |
| } |
| else |
| { |
| argoffset = align_up (argoffset, 16); |
| if (write_pass) |
| write_memory (sp + argoffset, val, 16); |
| argoffset += 16; |
| } |
| } |
| else if (len == 8 |
| && TYPE_CODE (type) == TYPE_CODE_ARRAY |
| && TYPE_VECTOR (type) |
| && tdep->ppc_ev0_regnum >= 0) |
| { |
| /* Vector parameter passed in an e500 register, or when |
| that runs out, 8 byte aligned stack location. Note |
| that since e500 vector and general purpose registers |
| both map onto the same underlying register set, a |
| "greg" and not a "vreg" is consumed here. A cooked |
| write stores the value in the correct locations |
| within the raw register cache. */ |
| if (greg <= 10) |
| { |
| if (write_pass) |
| regcache_cooked_write (current_regcache, |
| tdep->ppc_ev0_regnum + greg, |
| val); |
| greg++; |
| } |
| else |
| { |
| argoffset = align_up (argoffset, 8); |
| if (write_pass) |
| write_memory (sp + argoffset, val, 8); |
| argoffset += 8; |
| } |
| } |
| else |
| { |
| /* Reduce the parameter down to something that fits in a |
| "word". */ |
| char word[MAX_REGISTER_SIZE]; |
| memset (word, 0, MAX_REGISTER_SIZE); |
| if (len > tdep->wordsize |
| || TYPE_CODE (type) == TYPE_CODE_STRUCT |
| || TYPE_CODE (type) == TYPE_CODE_UNION) |
| { |
| /* Structs and large values are put on an 8 byte |
| aligned stack ... */ |
| structoffset = align_up (structoffset, 8); |
| if (write_pass) |
| write_memory (sp + structoffset, val, len); |
| /* ... and then a "word" pointing to that address is |
| passed as the parameter. */ |
| store_unsigned_integer (word, tdep->wordsize, |
| sp + structoffset); |
| structoffset += len; |
| } |
| else if (TYPE_CODE (type) == TYPE_CODE_INT) |
| /* Sign or zero extend the "int" into a "word". */ |
| store_unsigned_integer (word, tdep->wordsize, |
| unpack_long (type, val)); |
| else |
| /* Always goes in the low address. */ |
| memcpy (word, val, len); |
| /* Store that "word" in a register, or on the stack. |
| The words have "4" byte alignment. */ |
| if (greg <= 10) |
| { |
| if (write_pass) |
| regcache_cooked_write (regcache, |
| tdep->ppc_gp0_regnum + greg, |
| word); |
| greg++; |
| } |
| else |
| { |
| argoffset = align_up (argoffset, tdep->wordsize); |
| if (write_pass) |
| write_memory (sp + argoffset, word, tdep->wordsize); |
| argoffset += tdep->wordsize; |
| } |
| } |
| } |
| |
| /* Compute the actual stack space requirements. */ |
| if (!write_pass) |
| { |
| /* Remember the amount of space needed by the arguments. */ |
| argspace = argoffset; |
| /* Allocate space for both the arguments and the structures. */ |
| sp -= (argoffset + structoffset); |
| /* Ensure that the stack is still 16 byte aligned. */ |
| sp = align_down (sp, 16); |
| } |
| } |
| |
| /* Update %sp. */ |
| regcache_cooked_write_signed (regcache, SP_REGNUM, sp); |
| |
| /* Write the backchain (it occupies WORDSIZED bytes). */ |
| write_memory_signed_integer (sp, tdep->wordsize, saved_sp); |
| |
| /* Point the inferior function call's return address at the dummy's |
| breakpoint. */ |
| regcache_cooked_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr); |
| |
| return sp; |
| } |
| |
| /* Structures 8 bytes or less long are returned in the r3 & r4 |
| registers, according to the SYSV ABI. */ |
| int |
| ppc_sysv_abi_use_struct_convention (int gcc_p, struct type *value_type) |
| { |
| if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8) |
| && TYPE_VECTOR (value_type)) |
| return 0; |
| |
| return (TYPE_LENGTH (value_type) > 8); |
| } |