Prepare for radical source tree reorganization.zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 256 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/alpha/divqu.S b/REORG.TODO/sysdeps/alpha/divqu.S
new file mode 100644
index 0000000000..15101fa246
--- /dev/null
+++ b/REORG.TODO/sysdeps/alpha/divqu.S
@@ -0,0 +1,256 @@
+/* Copyright (C) 2004-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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/>.  */
+
+#include "div_libc.h"
+
+
+/* 64-bit unsigned long divide.  These are not normal C functions.  Argument
+   registers are t10 and t11, the result goes in t12.  Only t12 and AT may be
+   clobbered.
+
+   Theory of operation here is that we can use the FPU divider for virtually
+   all operands that we see: all dividend values between -2**53 and 2**53-1
+   can be computed directly.  Note that divisor values need not be checked
+   against that range because the rounded fp value will be close enough such
+   that the quotient is < 1, which will properly be truncated to zero when we
+   convert back to integer.
+
+   When the dividend is outside the range for which we can compute exact
+   results, we use the fp quotent as an estimate from which we begin refining
+   an exact integral value.  This reduces the number of iterations in the
+   shift-and-subtract loop significantly.
+
+   The FPCR save/restore is due to the fact that the EV6 _will_ set FPCR_INE
+   for cvttq/c even without /sui being set.  It will not, however, properly
+   raise the exception, so we don't have to worry about FPCR_INED being clear
+   and so dying by SIGFPE.  */
+
+	.text
+	.align	4
+	.globl	__divqu
+	.type	__divqu, @funcnoplt
+	.usepv	__divqu, no
+
+	cfi_startproc
+	cfi_return_column (RA)
+__divqu:
+	lda	sp, -FRAME(sp)
+	cfi_def_cfa_offset (FRAME)
+	CALL_MCOUNT
+
+	/* Get the fp divide insn issued as quickly as possible.  After
+	   that's done, we have at least 22 cycles until its results are
+	   ready -- all the time in the world to figure out how we're
+	   going to use the results.  */
+	stt	$f0, 0(sp)
+	excb
+	beq	Y, DIVBYZERO
+
+	stt	$f1, 8(sp)
+	stt	$f3, 48(sp)
+	cfi_rel_offset ($f0, 0)
+	cfi_rel_offset ($f1, 8)
+	cfi_rel_offset ($f3, 48)
+	mf_fpcr	$f3
+
+	_ITOFT2	X, $f0, 16, Y, $f1, 24
+	cvtqt	$f0, $f0
+	cvtqt	$f1, $f1
+	blt	X, $x_is_neg
+	divt/c	$f0, $f1, $f0
+
+	/* Check to see if Y was mis-converted as signed value.  */
+	ldt	$f1, 8(sp)
+	blt	Y, $y_is_neg
+
+	/* Check to see if X fit in the double as an exact value.  */
+	srl	X, 53, AT
+	bne	AT, $x_big
+
+	/* If we get here, we're expecting exact results from the division.
+	   Do nothing else besides convert and clean up.  */
+	cvttq/c	$f0, $f0
+	excb
+	mt_fpcr	$f3
+	_FTOIT	$f0, RV, 16
+
+	ldt	$f0, 0(sp)
+	ldt	$f3, 48(sp)
+	cfi_remember_state
+	cfi_restore ($f0)
+	cfi_restore ($f1)
+	cfi_restore ($f3)
+	cfi_def_cfa_offset (0)
+	lda	sp, FRAME(sp)
+	ret	$31, (RA), 1
+
+	.align	4
+	cfi_restore_state
+$x_is_neg:
+	/* If we get here, X is so big that bit 63 is set, which made the
+	   conversion come out negative.  Fix it up lest we not even get
+	   a good estimate.  */
+	ldah	AT, 0x5f80		/* 2**64 as float.  */
+	stt	$f2, 24(sp)
+	cfi_rel_offset ($f2, 24)
+	_ITOFS	AT, $f2, 16
+
+	.align	4
+	addt	$f0, $f2, $f0
+	unop
+	divt/c	$f0, $f1, $f0
+	unop
+
+	/* Ok, we've now the divide issued.  Continue with other checks.  */
+	ldt	$f1, 8(sp)
+	unop
+	ldt	$f2, 24(sp)
+	blt	Y, $y_is_neg
+	cfi_restore ($f1)
+	cfi_restore ($f2)
+	cfi_remember_state	/* for y_is_neg */
+
+	.align	4
+$x_big:
+	/* If we get here, X is large enough that we don't expect exact
+	   results, and neither X nor Y got mis-translated for the fp
+	   division.  Our task is to take the fp result, figure out how
+	   far it's off from the correct result and compute a fixup.  */
+	stq	t0, 16(sp)
+	stq	t1, 24(sp)
+	stq	t2, 32(sp)
+	stq	t3, 40(sp)
+	cfi_rel_offset (t0, 16)
+	cfi_rel_offset (t1, 24)
+	cfi_rel_offset (t2, 32)
+	cfi_rel_offset (t3, 40)
+
+#define Q	RV		/* quotient */
+#define R	t0		/* remainder */
+#define SY	t1		/* scaled Y */
+#define S	t2		/* scalar */
+#define QY	t3		/* Q*Y */
+
+	cvttq/c	$f0, $f0
+	_FTOIT	$f0, Q, 8
+	mulq	Q, Y, QY
+
+	.align	4
+	stq	t4, 8(sp)
+	excb
+	ldt	$f0, 0(sp)
+	mt_fpcr	$f3
+	cfi_rel_offset (t4, 8)
+	cfi_restore ($f0)
+
+	subq	QY, X, R
+	mov	Y, SY
+	mov	1, S
+	bgt	R, $q_high
+
+$q_high_ret:
+	subq	X, QY, R
+	mov	Y, SY
+	mov	1, S
+	bgt	R, $q_low
+
+$q_low_ret:
+	ldq	t4, 8(sp)
+	ldq	t0, 16(sp)
+	ldq	t1, 24(sp)
+	ldq	t2, 32(sp)
+
+	ldq	t3, 40(sp)
+	ldt	$f3, 48(sp)
+	lda	sp, FRAME(sp)
+	cfi_remember_state
+	cfi_restore (t0)
+	cfi_restore (t1)
+	cfi_restore (t2)
+	cfi_restore (t3)
+	cfi_restore (t4)
+	cfi_restore ($f3)
+	cfi_def_cfa_offset (0)
+	ret	$31, (RA), 1
+
+	.align	4
+	cfi_restore_state
+	/* The quotient that we computed was too large.  We need to reduce
+	   it by S such that Y*S >= R.  Obviously the closer we get to the
+	   correct value the better, but overshooting high is ok, as we'll
+	   fix that up later.  */
+0:
+	addq	SY, SY, SY
+	addq	S, S, S
+$q_high:
+	cmpult	SY, R, AT
+	bne	AT, 0b
+
+	subq	Q, S, Q
+	unop
+	subq	QY, SY, QY
+	br	$q_high_ret
+
+	.align	4
+	/* The quotient that we computed was too small.  Divide Y by the
+	   current remainder (R) and add that to the existing quotient (Q).
+	   The expectation, of course, is that R is much smaller than X.  */
+	/* Begin with a shift-up loop.  Compute S such that Y*S >= R.  We
+	   already have a copy of Y in SY and the value 1 in S.  */
+0:
+	addq	SY, SY, SY
+	addq	S, S, S
+$q_low:
+	cmpult	SY, R, AT
+	bne	AT, 0b
+
+	/* Shift-down and subtract loop.  Each iteration compares our scaled
+	   Y (SY) with the remainder (R); if SY <= R then X is divisible by
+	   Y's scalar (S) so add it to the quotient (Q).  */
+2:	addq	Q, S, t3
+	srl	S, 1, S
+	cmpule	SY, R, AT
+	subq	R, SY, t4
+
+	cmovne	AT, t3, Q
+	cmovne	AT, t4, R
+	srl	SY, 1, SY
+	bne	S, 2b
+
+	br	$q_low_ret
+
+	.align	4
+	cfi_restore_state
+$y_is_neg:
+	/* If we get here, Y is so big that bit 63 is set.  The results
+	   from the divide will be completely wrong.  Fortunately, the
+	   quotient must be either 0 or 1, so just compute it directly.  */
+	cmpule	Y, X, RV
+	excb
+	mt_fpcr	$f3
+	ldt	$f0, 0(sp)
+	ldt	$f3, 48(sp)
+	lda	sp, FRAME(sp)
+	cfi_restore ($f0)
+	cfi_restore ($f3)
+	cfi_def_cfa_offset (0)
+	ret	$31, (RA), 1
+
+	cfi_endproc
+	.size	__divqu, .-__divqu
+
+	DO_DIVBYZERO