gcc/libgcc/config/rl78/trampoline.S

140 lines
2.9 KiB
ArmAsm

/* libgcc routines for RL78
Copyright (C) 2011
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.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
/* RL78 Trampoline support
Since the RL78's RAM is not in the first 64k, we cannot "just" use a
function pointer to point to a trampoline on the stack. So, we
create N fixed trampolines that read from an array, and allocate
them as needed.
*/
r8 = 0xffef0
r10 = 0xffef2
r14 = 0xffef6
.data
.p2align 1
trampoline_array:
.macro stub n
.text
trampoline_\n:
.type trampoline_\n, @function
movw ax, !trampoline_chain_\n
movw r14, ax
movw ax, !trampoline_addr_\n
br ax
.size trampoline_\n, .-trampoline_\n
.data
trampoline_frame_\n:
.short 0
trampoline_stub_\n:
.short trampoline_\n
trampoline_chain_\n:
.short 0
trampoline_addr_\n:
.short 0
#define TO_FRAME 0
#define TO_STUB 2
#define TO_CHAIN 4
#define TO_ADDR 6
#define TO_SIZE 8
.endm
stub 0
stub 1
stub 2
stub 3
stub 4
stub 5
trampoline_array_end:
/* Given the function pointer in R8 and the static chain
pointer in R10, allocate a trampoline and return its address in
R8. */
.text
.global ___trampoline_init
.type ___trampoline_init, @function
___trampoline_init:
movw hl, #trampoline_array
1:
movw ax, [hl + TO_ADDR]
cmpw ax, #0
bz $2f
movw ax, hl
addw ax, #TO_SIZE
movw hl, ax
cmpw ax, #trampoline_array_end
bnz $1b
brk ; no more slots?
2: movw ax, r8
movw [hl + TO_ADDR], ax
movw ax, r10
movw [hl + TO_CHAIN], ax
movw ax, sp
movw [hl + TO_FRAME], ax
movw ax, [hl + TO_STUB]
movw r8, ax
ret
.size ___trampoline_init, . - ___trampoline_init
.global ___trampoline_uninit
.type ___trampoline_uninit, @function
___trampoline_uninit:
movw hl, #trampoline_array
movw ax, sp
movw bc, ax
1:
movw ax, [hl + TO_FRAME]
cmpw ax, bc
bc $2f
clrw ax
movw [hl + TO_ADDR], ax
2:
movw ax, hl
addw ax, #TO_SIZE
movw hl, ax
cmpw ax, #trampoline_array_end
bnz $1b
ret
.size ___trampoline_uninit, . - ___trampoline_uninit