u3copy_in_user.s

该文件是rt_linux

/* $Id: U3copy_in_user.S,v 1.4 2001/03/21 05:58:47 davem Exp $
 * U3memcpy.S: UltraSparc-III optimized copy within userspace.
 *
 * Copyright (C) 1999, 2000 David S. Miller ([e-mail])
 */

#ifdef __KERNEL__
#include <asm/visasm.h>
#include <asm/asi.h>
#undef SMALL_COPY_USES_FPU
#define EXNV(x,y,a,b)	\
98:	x,y;				\
	.section .fixup;		\
	.align 4;			\
99:	retl;				\
	 a, b, %o0;			\
	.section __ex_table;		\
	.align 4;			\
	.word 98b, 99b;			\
	.text;				\
	.align 4;
#define EXNV2(x,y,a,b)	\
98:	x,y;				\
	.section .fixup;		\
	.align 4;			\
99:	a, b, %o0;			\
	retl;				\
	 add %o0, 1, %o0;		\
	.section __ex_table;		\
	.align 4;			\
	.word 98b, 99b;			\
	.text;				\
	.align 4;
#define EXNV3(x,y,a,b)	\
98:	x,y;				\
	.section .fixup;		\
	.align 4;			\
99:	a, b, %o0;			\
	retl;				\
	 add %o0, 8, %o0;		\
	.section __ex_table;		\
	.align 4;			\
	.word 98b, 99b;			\
	.text;				\
	.align 4;
#define EX(x,y,a,b)			\
98:	x,y;				\
	.section .fixup;		\
	.align 4;			\
99:	VISExitHalf;			\
	retl;				\
	 a, b, %o0;			\
	.section __ex_table;		\
	.align 4;			\
	.word 98b, 99b;			\
	.text;				\
	.align 4;
#define EXBLK1(x,y)			\
98:	x,y;				\
	.section .fixup;		\
	.align 4;			\
99:	VISExitHalf;			\
	add %o4, 0x1c0, %o1;		\
	and %o2, (0x40 - 1), %o2;	\
	retl;				\
	 add %o1, %o2, %o0;		\
	.section __ex_table;		\
	.align 4;			\
	.word 98b, 99b;			\
	.text;				\
	.align 4;
#define EXBLK2(x,y)			\
98:	x,y;				\
	.section .fixup;		\
	.align 4;			\
99:	VISExitHalf;			\
	sll %o3, 6, %o3;		\
	and %o2, (0x40 - 1), %o2;	\
	add %o3, 0x80, %o1;		\
	retl;				\
	 add %o1, %o2, %o0;		\
	.section __ex_table;		\
	.align 4;			\
	.word 98b, 99b;			\
	.text;				\
	.align 4;
#define EXBLK3(x,y)			\
98:	x,y;				\
	.section .fixup;		\
	.align 4;			\
99:	VISExitHalf;			\
	and %o2, (0x40 - 1), %o2;	\
	retl;				\
	 add %o2, 0x80, %o0;		\
	.section __ex_table;		\
	.align 4;			\
	.word 98b, 99b;			\
	.text;				\
	.align 4;
#define EXBLK4(x,y)			\
98:	x,y;				\
	.section .fixup;		\
	.align 4;			\
99:	VISExitHalf;			\
	and %o2, (0x40 - 1), %o2;	\
	retl;				\
	 add %o2, 0x40, %o0;		\
	.section __ex_table;		\
	.align 4;			\
	.word 98b, 99b;			\
	.text;				\
	.align 4;
#else
#define ASI_AIUS 0x80
#define ASI_BLK_AIUS 0xf0
#define FPRS_FEF  0x04
#define VISEntryHalf rd %fprs, %o5; wr %g0, FPRS_FEF, %fprs
#define VISExitHalf and %o5, FPRS_FEF, %o5; wr %o5, 0x0, %fprs
#define SMALL_COPY_USES_FPU
#define EXNV(x,y,a,b)	x,y;
#define EXNV2(x,y,a,b)	x,y;
#define EXNV3(x,y,a,b)	x,y;
#define EX(x,y,a,b)	x,y;
#define EXBLK1(x,y)	x,y;
#define EXBLK2(x,y)	x,y;
#define EXBLK3(x,y)	x,y;
#define EXBLK4(x,y)	x,y;
#endif

	/* Special/non-trivial issues of this code:
	 *
	 * 1) %o5 is preserved from VISEntryHalf to VISExitHalf
	 * 2) Only low 32 FPU registers are used so that only the
	 *    lower half of the FPU register set is dirtied by this
	 *    code.  This is especially important in the kernel.
	 * 3) This code never prefetches cachelines past the end
	 *    of the source buffer.
	 *
	 *    XXX Actually, Cheetah can buffer up to 8 concurrent
	 *    XXX prefetches, revisit this...
	 */

	.text
	.align	32

	/* The cheetah's flexible spine, oversized liver, enlarged heart,
	 * slender muscular body, and claws make it the swiftest hunter
	 * in Africa and the fastest animal on land.  Can reach speeds
	 * of up to 2.4GB per second.
	 */

	.globl		U3copy_in_user
U3copy_in_user: /* %o0=dst, %o1=src, %o2=len */
	/* Writing to %asi is _expensive_ so we hardcode it.
	 * Reading %asi to check for KERNEL_DS is comparatively
	 * cheap.
	 */
	rd		%asi, %g1			! MS	Group	(4 cycles)
	cmp		%g1, ASI_AIUS			! A0	Group
	bne		U3memcpy			! BR
	 nop						! A1
#ifndef __KERNEL__
	/* Save away original 'dst' for memcpy return value. */
	mov		%o0, %g3			! A0	Group
#endif
	/* Anything to copy at all? */
	cmp		%o2, 0				! A1
	ble,pn		%icc, U3copy_in_user_short_ret	! BR

	/* Extremely small copy? */
	 cmp		%o2, 31				! A0	Group
	ble,pn		%icc, U3copy_in_user_short	! BR

	/* Large enough to use unrolled prefetch loops? */
	 cmp		%o2, 0x100			! A1
	bge,a,pt	%icc, U3copy_in_user_enter	! BR	Group
	 andcc		%o0, 0x3f, %g2			! A0

	ba,pt		%xcc, U3copy_in_user_toosmall	! BR	Group
	 andcc		%o0, 0x7, %g2			! A0

	.align		32
U3copy_in_user_short:
	/* Copy %o2 bytes from src to dst, one byte at a time. */
	EXNV(lduba [%o1 + 0x00] %asi, %o3, add %o2, %g0)! MS	Group
	add		%o1, 0x1, %o1			! A0
	add		%o0, 0x1, %o0			! A1
	subcc		%o2, 1, %o2			! A0	Group

	bg,pt		%icc, U3copy_in_user_short	! BR
	 EXNV(stba %o3, [%o0 + -1] %asi, add %o2, 1)	! MS	Group (1-cycle stall)

U3copy_in_user_short_ret:
#ifdef __KERNEL__
	retl						! BR	Group (0-4 cycle stall)
	 clr		%o0				! A0
#else
	retl						! BR	Group (0-4 cycle stall)
	 mov		%g3, %o0			! A0
#endif

	/* Here len >= (6 * 64) and condition codes reflect execution
	 * of "andcc %o0, 0x7, %g2", done by caller.
	 */
	.align		64
U3copy_in_user_enter:
	/* Is 'dst' already aligned on an 64-byte boundary? */
	be,pt		%xcc, 2f			! BR

	/* Compute abs((dst & 0x3f) - 0x40) into %g2.  This is the number
	 * of bytes to copy to make 'dst' 64-byte aligned.  We pre-
	 * subtract this from 'len'.
	 */
	 sub		%g2, 0x40, %g2			! A0	Group
	sub		%g0, %g2, %g2			! A0	Group
	sub		%o2, %g2, %o2			! A0	Group

	/* Copy %g2 bytes from src to dst, one byte at a time. */
1:	EXNV(lduba [%o1 + 0x00] %asi, %o3, add %o2, %g2)! MS	(Group)
	add		%o1, 0x1, %o1			! A1
	add		%o0, 0x1, %o0			! A0	Group
	subcc		%g2, 0x1, %g2			! A1

	bg,pt		%icc, 1b			! BR	Group
	 EXNV2(stba %o3, [%o0 + -1] %asi, add %o2, %g2)	! MS	Group

2:	VISEntryHalf					! MS+MS
	and		%o1, 0x7, %g1			! A1
	ba,pt		%xcc, U3copy_in_user_begin	! BR
	 alignaddr	%o1, %g0, %o1			! MS	      (Break-after)

	.align		64
U3copy_in_user_begin:
	prefetcha	[%o1 + 0x000] %asi, #one_read	! MS	Group1
	prefetcha	[%o1 + 0x040] %asi, #one_read	! MS	Group2
	andn		%o2, (0x40 - 1), %o4		! A0
	prefetcha	[%o1 + 0x080] %asi, #one_read	! MS	Group3
	cmp		%o4, 0x140			! A0
	prefetcha	[%o1 + 0x0c0] %asi, #one_read	! MS	Group4
	EX(ldda [%o1 + 0x000] %asi, %f0, add %o2, %g0)	! MS	Group5 (%f0 results at G8)
	bge,a,pt	%icc, 1f			! BR

	 prefetcha	[%o1 + 0x100] %asi, #one_read	! MS	Group6
1:	EX(ldda [%o1 + 0x008] %asi, %f2, add %o2, %g0)	! AX	       (%f2 results at G9)
	cmp		%o4, 0x180			! A1
	bge,a,pt	%icc, 1f			! BR
	 prefetcha	[%o1 + 0x140] %asi, #one_read	! MS	Group7
1:	EX(ldda [%o1 + 0x010] %asi, %f4, add %o2, %g0)	! AX	       (%f4 results at G10)
	cmp		%o4, 0x1c0			! A1
	bge,a,pt	%icc, 1f			! BR

	 prefetcha	[%o1 + 0x180] %asi, #one_read	! MS	Group8
1:	faligndata	%f0, %f2, %f16			! FGA	Group9 (%f16 at G12)
	EX(ldda [%o1 + 0x018] %asi, %f6, add %o2, %g0)	! AX	       (%f6 results at G12)
	faligndata	%f2, %f4, %f18			! FGA	Group10 (%f18 results at G13)
	EX(ldda [%o1 + 0x020] %asi, %f8, add %o2, %g0)	! MS	        (%f8 results at G13)
	faligndata	%f4, %f6, %f20			! FGA	Group12	(1-cycle stall,%f20 at G15)
	EX(ldda [%o1 + 0x028] %asi, %f10, add %o2, %g0)	! MS		(%f10 results at G15)
	faligndata	%f6, %f8, %f22			! FGA	Group13 (%f22 results at G16)
	
	EX(ldda [%o1 + 0x030] %asi, %f12, add %o2, %g0)	! MS		(%f12 results at G16)
	faligndata	%f8, %f10, %f24			! FGA	Group15 (1-cycle stall,%f24 at G18)
	EX(ldda [%o1 + 0x038] %asi, %f14, add %o2, %g0)	! MS		(%f14 results at G18)
	faligndata	%f10, %f12, %f26		! FGA	Group16 (%f26 results at G19)
	EX(ldda [%o1 + 0x040] %asi, %f0, add %o2, %g0)	! MS		(%f0 results at G19)