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Diffstat (limited to 'gcc-4.9/gcc/config/m32c/m32c.abi')
| -rw-r--r-- | gcc-4.9/gcc/config/m32c/m32c.abi | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/config/m32c/m32c.abi b/gcc-4.9/gcc/config/m32c/m32c.abi new file mode 100644 index 000000000..69e6761d1 --- /dev/null +++ b/gcc-4.9/gcc/config/m32c/m32c.abi @@ -0,0 +1,131 @@ + Target Definitions for R8C/M16C/M32C + Copyright (C) 2005-2014 Free Software Foundation, Inc. + Contributed by Red Hat. + + This file is part of GCC. + + GCC 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 3, or (at your + option) any later version. + + GCC 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 GCC; see the file COPYING3. If not see + <http://www.gnu.org/licenses/>. + + +These are just some random notes I used during development of this +port. Please don't consider these to be "official" specifications, +just additional information to help make the code easier to +understand. + + +Frame +===== + + +-------------------- + | incoming args + +-------------------- + | return Address +osp -> +-------------------- + | saved fp +fp -> +-------------------- + | local data + +-------------------- + | saved regs + +-------------------- + | outgoing args (opt) +sp -> +-------------------- + +Argument Passing +================ + +r8c, m16c +--------- + +First arg may be passed in r1l or r1 if it (1) fits (QImode or +HImode), (2) is named, and (3) is an integer or pointer type (no +structs, floats, etc). Otherwise, it's passed on the stack. + +Second arg may be passed in r2, same restrictions (but not QImode), +even if the first arg is passed on the stack. + +Third and further args are passed on the stack. No padding is used, +stack "alignment" is 8 bits. + +m32cm, m32c +----------- +First arg may be passed in r0l or r0, same restrictions as above. + +Second and further args are passed on the stack. Padding is used +after QImode parameters (i.e. lower-addressed byte is the value, +higher-addressed byte is the padding), stack "alignment" is 16 bits. + + +Return Value +============ + +r8c, m16c +--------- + +QImode in r0l +HImode in r0 +near pointer in r0 +(desired) +SImode in r2r0 +far pointer in r2r0 +(actual) +Anything bigger than 16 bits is returned in memory, at mem0 (mem0 +through mem15 are provided by libgcc.a) + +Aggregate values (regardless of size) are returned by pushing a +pointer to a temporary area on the stack after the args are pushed. +The function fills in this area with the value. Note that this +pointer on the stack does not affect how register arguments, if any, +are configured. + +m32cm, m32c +----------- +Same. + + +Registers Preserved Across Calls +================================ + +r8c, m16c +--------- +sb, fb, sp (i.e. nearly all registers are call clobbered) + +m32cm, m32c +----------- +r1, r2, r3, a0, a1, sb, fb, sp +(except when used for return values) + + +Interrupt Handlers +================== + +The stack frame is slightly different for interrupt handlers, because +(1) we don't have a usable parent frame, and (2) we have to use +special instructions to return and thus must save/restore everything +differently. + + +-------------------- + | program state +osp -> +-------------------- + | return address + +-------------------- + | saved r0..fp (pushm) +fp -> +-------------------- + | local data + +-------------------- + | saved regs mem0..mem15 + +-------------------- + | outgoing args (opt) +sp -> +-------------------- + |