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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/mips/dec/prom/call_o32.S
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/*

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 *	O32 interface for the 64 (or N32) ABI.

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 *

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 *	Copyright (C) 2002  Maciej W. Rozycki

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 *

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 *	This program is free software; you can redistribute it and/or

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 *	modify it under the terms of the GNU General Public License

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 *	as published by the Free Software Foundation; either version

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 *	2 of the License, or (at your option) any later version.

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 */

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#include <asm/asm.h>

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#include <asm/regdef.h>

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/* Maximum number of arguments supported.  Must be even!  */

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#define O32_ARGC	32

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/* Number of static registers we save.  */

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#define O32_STATC	11

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/* Frame size for both of the above.  */

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#define O32_FRAMESZ	(4 * O32_ARGC + SZREG * O32_STATC)

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		.text

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/*

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 * O32 function call dispatcher, for interfacing 32-bit ROM routines.

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 *

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 * The standard 64 (N32) calling sequence is supported, with a0

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 * holding a function pointer, a1-a7 -- its first seven arguments

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 * and the stack -- remaining ones (up to O32_ARGC, including a1-a7).

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 * Static registers, gp and fp are preserved, v0 holds a result.

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 * This code relies on the called o32 function for sp and ra

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 * restoration and thus both this dispatcher and the current stack

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 * have to be placed in a KSEGx (or KUSEG) address space.  Any

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 * pointers passed have to point to addresses within one of these

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 * spaces as well.

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 */

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NESTED(call_o32, O32_FRAMESZ, ra)

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		REG_SUBU	sp,O32_FRAMESZ

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		REG_S		ra,O32_FRAMESZ-1*SZREG(sp)

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		REG_S		fp,O32_FRAMESZ-2*SZREG(sp)

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		REG_S		gp,O32_FRAMESZ-3*SZREG(sp)

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		REG_S		s7,O32_FRAMESZ-4*SZREG(sp)

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		REG_S		s6,O32_FRAMESZ-5*SZREG(sp)

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		REG_S		s5,O32_FRAMESZ-6*SZREG(sp)

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		REG_S		s4,O32_FRAMESZ-7*SZREG(sp)

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		REG_S		s3,O32_FRAMESZ-8*SZREG(sp)

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		REG_S		s2,O32_FRAMESZ-9*SZREG(sp)

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		REG_S		s1,O32_FRAMESZ-10*SZREG(sp)

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		REG_S		s0,O32_FRAMESZ-11*SZREG(sp)

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		move		jp,a0

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		sll		a0,a1,zero

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		sll		a1,a2,zero

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		sll		a2,a3,zero

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		sll		a3,a4,zero

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		sw		a5,0x10(sp)

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		sw		a6,0x14(sp)

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		sw		a7,0x18(sp)

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		PTR_LA		t0,O32_FRAMESZ(sp)

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		PTR_LA		t1,0x1c(sp)

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		li		t2,O32_ARGC-7

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1:

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		lw		t3,(t0)

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		REG_ADDU	t0,SZREG

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		sw		t3,(t1)

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		REG_SUBU	t2,1

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		REG_ADDU	t1,4

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		bnez		t2,1b

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		jalr		jp

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		REG_L		s0,O32_FRAMESZ-11*SZREG(sp)

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		REG_L		s1,O32_FRAMESZ-10*SZREG(sp)

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		REG_L		s2,O32_FRAMESZ-9*SZREG(sp)

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		REG_L		s3,O32_FRAMESZ-8*SZREG(sp)

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		REG_L		s4,O32_FRAMESZ-7*SZREG(sp)

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		REG_L		s5,O32_FRAMESZ-6*SZREG(sp)

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		REG_L		s6,O32_FRAMESZ-5*SZREG(sp)

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		REG_L		s7,O32_FRAMESZ-4*SZREG(sp)

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		REG_L		gp,O32_FRAMESZ-3*SZREG(sp)

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		REG_L		fp,O32_FRAMESZ-2*SZREG(sp)

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		REG_L		ra,O32_FRAMESZ-1*SZREG(sp)

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		REG_ADDU	sp,O32_FRAMESZ

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		jr		ra

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END(call_o32)

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