Add nios2 port.

2026-11-09 17:47:19 +00:00 · 2013-10-15 15:33:59 -04:00
parent 2f5626ce02
commit 16b93a211b
10 changed files with 621 additions and 54 deletions
@@ -0,0 +1,136 @@
+/* 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
+