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-rw-r--r--ports/sysdeps/ia64/bzero.S314
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diff --git a/ports/sysdeps/ia64/bzero.S b/ports/sysdeps/ia64/bzero.S
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+/* Optimized version of the standard bzero() function.
+   This file is part of the GNU C Library.
+   Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
+   Contributed by Dan Pop for Itanium <Dan.Pop@cern.ch>.
+   Rewritten for McKinley by Sverre Jarp, HP Labs/CERN <Sverre.Jarp@cern.ch>
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Return: dest
+
+   Inputs:
+        in0:    dest
+        in1:    count
+
+   The algorithm is fairly straightforward: set byte by byte until we
+   we get to a 16B-aligned address, then loop on 128 B chunks using an
+   early store as prefetching, then loop on 32B chucks, then clear remaining
+   words, finally clear remaining bytes.
+   Since a stf.spill f0 can store 16B in one go, we use this instruction
+   to get peak speed.  */
+
+#include <sysdep.h>
+#undef ret
+
+#define dest		in0
+#define	cnt		in1
+
+#define tmp		r31
+#define save_lc		r30
+#define ptr0		r29
+#define ptr1		r28
+#define ptr2		r27
+#define ptr3		r26
+#define ptr9 		r24
+#define	loopcnt		r23
+#define linecnt		r22
+#define bytecnt		r21
+
+// This routine uses only scratch predicate registers (p6 - p15)
+#define p_scr		p6	// default register for same-cycle branches
+#define p_unalgn	p9
+#define p_y		p11
+#define p_n		p12
+#define p_yy		p13
+#define p_nn		p14
+
+#define movi0		mov
+
+#define MIN1		15
+#define MIN1P1HALF	8
+#define LINE_SIZE	128
+#define LSIZE_SH        7			// shift amount
+#define PREF_AHEAD	8
+
+#define USE_FLP
+#if defined(USE_INT)
+#define store		st8
+#define myval		r0
+#elif defined(USE_FLP)
+#define store		stf8
+#define myval		f0
+#endif
+
+.align	64
+ENTRY(bzero)
+{ .mmi
+	.prologue
+	alloc	tmp = ar.pfs, 2, 0, 0, 0
+	lfetch.nt1 [dest]
+	.save   ar.lc, save_lc
+	movi0	save_lc = ar.lc
+} { .mmi
+	.body
+	mov	ret0 = dest		// return value
+	nop.m	0
+	cmp.eq	p_scr, p0 = cnt, r0
+;; }
+{ .mmi
+	and	ptr2 = -(MIN1+1), dest	// aligned address
+	and	tmp = MIN1, dest	// prepare to check for alignment
+	tbit.nz p_y, p_n = dest, 0	// Do we have an odd address? (M_B_U)
+} { .mib
+	mov	ptr1 = dest
+	nop.i	0
+(p_scr)	br.ret.dpnt.many rp		// return immediately if count = 0
+;; }
+{ .mib
+	cmp.ne	p_unalgn, p0 = tmp, r0
+} { .mib					// NB: # of bytes to move is 1
+	sub	bytecnt = (MIN1+1), tmp		//     higher than loopcnt
+	cmp.gt	p_scr, p0 = 16, cnt		// is it a minimalistic task?
+(p_scr)	br.cond.dptk.many .move_bytes_unaligned	// go move just a few (M_B_U)
+;; }
+{ .mmi
+(p_unalgn) add	ptr1 = (MIN1+1), ptr2		// after alignment
+(p_unalgn) add	ptr2 = MIN1P1HALF, ptr2		// after alignment
+(p_unalgn) tbit.nz.unc p_y, p_n = bytecnt, 3	// should we do a st8 ?
+;; }
+{ .mib
+(p_y)	add	cnt = -8, cnt
+(p_unalgn) tbit.nz.unc p_yy, p_nn = bytecnt, 2	// should we do a st4 ?
+} { .mib
+(p_y)	st8	[ptr2] = r0,-4
+(p_n)	add	ptr2 = 4, ptr2
+;; }
+{ .mib
+(p_yy)	add	cnt = -4, cnt
+(p_unalgn) tbit.nz.unc p_y, p_n = bytecnt, 1	// should we do a st2 ?
+} { .mib
+(p_yy)	st4	[ptr2] = r0,-2
+(p_nn)	add	ptr2 = 2, ptr2
+;; }
+{ .mmi
+	mov	tmp = LINE_SIZE+1		// for compare
+(p_y)	add	cnt = -2, cnt
+(p_unalgn) tbit.nz.unc p_yy, p_nn = bytecnt, 0	// should we do a st1 ?
+} { .mmi
+	nop.m	0
+(p_y)	st2	[ptr2] = r0,-1
+(p_n)	add	ptr2 = 1, ptr2
+;; }
+
+{ .mmi
+(p_yy)	st1	[ptr2] = r0
+  	cmp.gt	p_scr, p0 = tmp, cnt		// is it a minimalistic task?
+} { .mbb
+(p_yy)	add	cnt = -1, cnt
+(p_scr)	br.cond.dpnt.many .fraction_of_line	// go move just a few
+;; }
+{ .mib
+	nop.m 	0
+	shr.u	linecnt = cnt, LSIZE_SH
+	nop.b	0
+;; }
+
+	.align 32
+.l1b:	// ------------------//  L1B: store ahead into cache lines; fill later
+{ .mmi
+	and	tmp = -(LINE_SIZE), cnt		// compute end of range
+	mov	ptr9 = ptr1			// used for prefetching
+	and	cnt = (LINE_SIZE-1), cnt	// remainder
+} { .mmi
+	mov	loopcnt = PREF_AHEAD-1		// default prefetch loop
+	cmp.gt	p_scr, p0 = PREF_AHEAD, linecnt	// check against actual value
+;; }
+{ .mmi
+(p_scr)	add	loopcnt = -1, linecnt
+	add	ptr2 = 16, ptr1	// start of stores (beyond prefetch stores)
+	add	ptr1 = tmp, ptr1	// first address beyond total range
+;; }
+{ .mmi
+	add	tmp = -1, linecnt	// next loop count
+	movi0	ar.lc = loopcnt
+;; }
+.pref_l1b:
+{ .mib
+	stf.spill [ptr9] = f0, 128	// Do stores one cache line apart
+	nop.i   0
+	br.cloop.dptk.few .pref_l1b
+;; }
+{ .mmi
+	add	ptr0 = 16, ptr2		// Two stores in parallel
+	movi0	ar.lc = tmp
+;; }
+.l1bx:
+ { .mmi
+	stf.spill [ptr2] = f0, 32
+	stf.spill [ptr0] = f0, 32
+ ;; }
+ { .mmi
+	stf.spill [ptr2] = f0, 32
+	stf.spill [ptr0] = f0, 32
+ ;; }
+ { .mmi
+	stf.spill [ptr2] = f0, 32
+	stf.spill [ptr0] = f0, 64
+ 	cmp.lt	p_scr, p0 = ptr9, ptr1	// do we need more prefetching?
+ ;; }
+{ .mmb
+	stf.spill [ptr2] = f0, 32
+(p_scr)	stf.spill [ptr9] = f0, 128
+	br.cloop.dptk.few .l1bx
+;; }
+{ .mib
+	cmp.gt  p_scr, p0 = 8, cnt	// just a few bytes left ?
+(p_scr)	br.cond.dpnt.many  .move_bytes_from_alignment
+;; }
+
+.fraction_of_line:
+{ .mib
+	add	ptr2 = 16, ptr1
+	shr.u	loopcnt = cnt, 5   	// loopcnt = cnt / 32
+;; }
+{ .mib
+	cmp.eq	p_scr, p0 = loopcnt, r0
+	add	loopcnt = -1, loopcnt
+(p_scr)	br.cond.dpnt.many .store_words
+;; }
+{ .mib
+	and	cnt = 0x1f, cnt		// compute the remaining cnt
+	movi0   ar.lc = loopcnt
+;; }
+	.align 32
+.l2:	// -----------------------------//  L2A:  store 32B in 2 cycles
+{ .mmb
+	store	[ptr1] = myval, 8
+	store	[ptr2] = myval, 8
+;; } { .mmb
+	store	[ptr1] = myval, 24
+	store	[ptr2] = myval, 24
+	br.cloop.dptk.many .l2
+;; }
+.store_words:
+{ .mib
+	cmp.gt	p_scr, p0 = 8, cnt	// just a few bytes left ?
+(p_scr)	br.cond.dpnt.many .move_bytes_from_alignment	// Branch
+;; }
+
+{ .mmi
+	store	[ptr1] = myval, 8	// store
+	cmp.le	p_y, p_n = 16, cnt	//
+	add	cnt = -8, cnt		// subtract
+;; }
+{ .mmi
+(p_y)	store	[ptr1] = myval, 8	// store
+(p_y)	cmp.le.unc p_yy, p_nn = 16, cnt
+(p_y)	add	cnt = -8, cnt		// subtract
+;; }
+{ .mmi					// store
+(p_yy)	store	[ptr1] = myval, 8
+(p_yy)	add	cnt = -8, cnt		// subtract
+;; }
+
+.move_bytes_from_alignment:
+{ .mib
+	cmp.eq	p_scr, p0 = cnt, r0
+	tbit.nz.unc p_y, p0 = cnt, 2	// should we terminate with a st4 ?
+(p_scr)	br.cond.dpnt.few .restore_and_exit
+;; }
+{ .mib
+(p_y)	st4	[ptr1] = r0,4
+	tbit.nz.unc p_yy, p0 = cnt, 1	// should we terminate with a st2 ?
+;; }
+{ .mib
+(p_yy)	st2	[ptr1] = r0,2
+	tbit.nz.unc p_y, p0 = cnt, 0	// should we terminate with a st1 ?
+;; }
+
+{ .mib
+(p_y)	st1	[ptr1] = r0
+;; }
+.restore_and_exit:
+{ .mib
+	nop.m	0
+	movi0	ar.lc = save_lc
+	br.ret.sptk.many rp
+;; }
+
+.move_bytes_unaligned:
+{ .mmi
+       .pred.rel "mutex",p_y, p_n
+       .pred.rel "mutex",p_yy, p_nn
+(p_n)	cmp.le  p_yy, p_nn = 4, cnt
+(p_y)	cmp.le  p_yy, p_nn = 5, cnt
+(p_n)	add	ptr2 = 2, ptr1
+} { .mmi
+(p_y)	add	ptr2 = 3, ptr1
+(p_y)	st1	[ptr1] = r0, 1		// fill 1 (odd-aligned) byte
+(p_y)	add	cnt = -1, cnt		// [15, 14 (or less) left]
+;; }
+{ .mmi
+(p_yy)	cmp.le.unc p_y, p0 = 8, cnt
+	add	ptr3 = ptr1, cnt	// prepare last store
+	movi0	ar.lc = save_lc
+} { .mmi
+(p_yy)	st2	[ptr1] = r0, 4		// fill 2 (aligned) bytes
+(p_yy)	st2	[ptr2] = r0, 4		// fill 2 (aligned) bytes
+(p_yy)	add	cnt = -4, cnt		// [11, 10 (o less) left]
+;; }
+{ .mmi
+(p_y)	cmp.le.unc p_yy, p0 = 8, cnt
+	add	ptr3 = -1, ptr3		// last store
+	tbit.nz p_scr, p0 = cnt, 1	// will there be a st2 at the end ?
+} { .mmi
+(p_y)	st2	[ptr1] = r0, 4		// fill 2 (aligned) bytes
+(p_y)	st2	[ptr2] = r0, 4		// fill 2 (aligned) bytes
+(p_y)	add	cnt = -4, cnt		// [7, 6 (or less) left]
+;; }
+{ .mmi
+(p_yy)	st2	[ptr1] = r0, 4		// fill 2 (aligned) bytes
+(p_yy)	st2	[ptr2] = r0, 4		// fill 2 (aligned) bytes
+					// [3, 2 (or less) left]
+	tbit.nz p_y, p0 = cnt, 0	// will there be a st1 at the end ?
+} { .mmi
+(p_yy)	add	cnt = -4, cnt
+;; }
+{ .mmb
+(p_scr)	st2	[ptr1] = r0		// fill 2 (aligned) bytes
+(p_y)	st1	[ptr3] = r0		// fill last byte (using ptr3)
+	br.ret.sptk.many rp
+;; }
+END(bzero)
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-12-01 22:36:41 +0000