1/*
2 *	arch/mips/dec/prom/call_o32.S
3 *
4 *	O32 interface for the 64 (or N32) ABI.
5 *
6 *	Copyright (C) 2002  Maciej W. Rozycki
7 *
8 *	This program is free software; you can redistribute it and/or
9 *	modify it under the terms of the GNU General Public License
10 *	as published by the Free Software Foundation; either version
11 *	2 of the License, or (at your option) any later version.
12 */
13
14#include <asm/asm.h>
15#include <asm/regdef.h>
16
17/* Maximum number of arguments supported.  Must be even!  */
18#define O32_ARGC	32
19/* Number of static registers we save.  */
20#define O32_STATC	11
21/* Frame size for both of the above.  */
22#define O32_FRAMESZ	(4 * O32_ARGC + SZREG * O32_STATC)
23
24		.text
25
26/*
27 * O32 function call dispatcher, for interfacing 32-bit ROM routines.
28 *
29 * The standard 64 (N32) calling sequence is supported, with a0
30 * holding a function pointer, a1-a7 -- its first seven arguments
31 * and the stack -- remaining ones (up to O32_ARGC, including a1-a7).
32 * Static registers, gp and fp are preserved, v0 holds a result.
33 * This code relies on the called o32 function for sp and ra
34 * restoration and thus both this dispatcher and the current stack
35 * have to be placed in a KSEGx (or KUSEG) address space.  Any
36 * pointers passed have to point to addresses within one of these
37 * spaces as well.
38 */
39NESTED(call_o32, O32_FRAMESZ, ra)
40		REG_SUBU	sp,O32_FRAMESZ
41
42		REG_S		ra,O32_FRAMESZ-1*SZREG(sp)
43		REG_S		fp,O32_FRAMESZ-2*SZREG(sp)
44		REG_S		gp,O32_FRAMESZ-3*SZREG(sp)
45		REG_S		s7,O32_FRAMESZ-4*SZREG(sp)
46		REG_S		s6,O32_FRAMESZ-5*SZREG(sp)
47		REG_S		s5,O32_FRAMESZ-6*SZREG(sp)
48		REG_S		s4,O32_FRAMESZ-7*SZREG(sp)
49		REG_S		s3,O32_FRAMESZ-8*SZREG(sp)
50		REG_S		s2,O32_FRAMESZ-9*SZREG(sp)
51		REG_S		s1,O32_FRAMESZ-10*SZREG(sp)
52		REG_S		s0,O32_FRAMESZ-11*SZREG(sp)
53
54		move		jp,a0
55
56		sll		a0,a1,zero
57		sll		a1,a2,zero
58		sll		a2,a3,zero
59		sll		a3,a4,zero
60		sw		a5,0x10(sp)
61		sw		a6,0x14(sp)
62		sw		a7,0x18(sp)
63
64		PTR_LA		t0,O32_FRAMESZ(sp)
65		PTR_LA		t1,0x1c(sp)
66		li		t2,O32_ARGC-7
671:
68		lw		t3,(t0)
69		REG_ADDU	t0,SZREG
70		sw		t3,(t1)
71		REG_SUBU	t2,1
72		REG_ADDU	t1,4
73		bnez		t2,1b
74
75		jalr		jp
76
77		REG_L		s0,O32_FRAMESZ-11*SZREG(sp)
78		REG_L		s1,O32_FRAMESZ-10*SZREG(sp)
79		REG_L		s2,O32_FRAMESZ-9*SZREG(sp)
80		REG_L		s3,O32_FRAMESZ-8*SZREG(sp)
81		REG_L		s4,O32_FRAMESZ-7*SZREG(sp)
82		REG_L		s5,O32_FRAMESZ-6*SZREG(sp)
83		REG_L		s6,O32_FRAMESZ-5*SZREG(sp)
84		REG_L		s7,O32_FRAMESZ-4*SZREG(sp)
85		REG_L		gp,O32_FRAMESZ-3*SZREG(sp)
86		REG_L		fp,O32_FRAMESZ-2*SZREG(sp)
87		REG_L		ra,O32_FRAMESZ-1*SZREG(sp)
88
89		REG_ADDU	sp,O32_FRAMESZ
90		jr		ra
91END(call_o32)
92