/* Low-level libffi support for Altera Nios II.
Copyright (c) 2013 Mentor Graphics.
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
``Software''), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/* This function is declared on the C side as
extern UINT64 ffi_call_sysv (void (*arghook) (char *, extended_cif *),
extended_cif *ecif,
unsigned nbytes,
void (*fn) (void));
On input, the arguments appear as
r4 = arghook
r5 = ecif
r6 = nbytes
r7 = fn
*/
.section .text
.align 2
.global ffi_call_sysv
.type ffi_call_sysv, @function
ffi_call_sysv:
.cfi_startproc
/* Create the stack frame, saving r16 so we can use it locally. */
addi sp, sp, -12
.cfi_def_cfa_offset 12
stw ra, 8(sp)
stw fp, 4(sp)
stw r16, 0(sp)
.cfi_offset 31, -4
.cfi_offset 28, -8
.cfi_offset 16, -12
mov fp, sp
.cfi_def_cfa_register 28
mov r16, r7
/* Adjust the stack pointer to create the argument buffer
nbytes long. */
sub sp, sp, r6
/* Call the arghook function. */
mov r2, r4 /* fn */
mov r4, sp /* argbuffer */
callr r2 /* r5 already contains ecif */
/* Pop off the first 16 bytes of the argument buffer on the stack,
transferring the contents to the argument registers. */
ldw r4, 0(sp)
ldw r5, 4(sp)
ldw r6, 8(sp)
ldw r7, 12(sp)
addi sp, sp, 16
/* Call the user function, which leaves its result in r2 and r3. */
callr r16
/* Pop off the stack frame. */
mov sp, fp
ldw ra, 8(sp)
ldw fp, 4(sp)
ldw r16, 0(sp)
addi sp, sp, 12
ret
.cfi_endproc
.size ffi_call_sysv, .-ffi_call_sysv
/* Closure trampolines jump here after putting the C helper address
in r9 and the closure pointer in r10. The user-supplied arguments
to the closure are in the normal places, in r4-r7 and on the
stack. Push the register arguments on the stack too and then call the
C helper function to deal with them. */
.section .text
.align 2
.global ffi_closure_sysv
.type ffi_closure_sysv, @function
ffi_closure_sysv:
.cfi_startproc
/* Create the stack frame, pushing the register args on the stack
just below the stack args. This is the same trick illustrated
in Figure 7-3 in the Nios II Processor Reference Handbook, used
for variable arguments and structures passed by value. */
addi sp, sp, -20
.cfi_def_cfa_offset 20
stw ra, 0(sp)
.cfi_offset 31, -20
stw r4, 4(sp)
.cfi_offset 4, -16
stw r5, 8(sp)
.cfi_offset 5, -12
stw r6, 12(sp)
.cfi_offset 6, -8
stw r7, 16(sp)
.cfi_offset 7, -4
/* Call the helper.
r4 = pointer to arguments on stack
r5 = closure pointer (loaded in r10 by the trampoline)
r9 = address of helper function (loaded by trampoline) */
addi r4, sp, 4
mov r5, r10
callr r9
/* Pop the stack and return. */
ldw ra, 0(sp)
addi sp, sp, 20
.cfi_def_cfa_offset -20
ret
.cfi_endproc
.size ffi_closure_sysv, .-ffi_closure_sysv
