Message-Id: <1307988875-21690-1-git-send-email-geert@linux-m68k.org>
Date:	Mon, 13 Jun 2011 20:14:35 +0200
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Jonathan Elchison <jelchison@...il.com>, linux-m68k@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org,
	Geert Uytterhoeven <geert@...ux-m68k.org>
Subject: [PATCH] m68k/math-emu: Remove commented out old code

It's been unused for ages, and contains bugs (e.g. incorrect shifts in
lsl64()).

Reported-by: Jonathan Elchison <jelchison@...il.com>
Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
---
 arch/m68k/math-emu/multi_arith.h |  530 --------------------------------------
 1 files changed, 0 insertions(+), 530 deletions(-)

diff --git a/arch/m68k/math-emu/multi_arith.h b/arch/m68k/math-emu/multi_arith.h
index 4ad0ca9..4b5eb3d 100644
--- a/arch/m68k/math-emu/multi_arith.h
+++ b/arch/m68k/math-emu/multi_arith.h
@@ -19,246 +19,6 @@
 #ifndef MULTI_ARITH_H
 #define MULTI_ARITH_H
 
-#if 0	/* old code... */
-
-/* Unsigned only, because we don't need signs to multiply and divide. */
-typedef unsigned int int128[4];
-
-/* Word order */
-enum {
-	MSW128,
-	NMSW128,
-	NLSW128,
-	LSW128
-};
-
-/* big-endian */
-#define LO_WORD(ll) (((unsigned int *) &ll)[1])
-#define HI_WORD(ll) (((unsigned int *) &ll)[0])
-
-/* Convenience functions to stuff various integer values into int128s */
-
-static inline void zero128(int128 a)
-{
-	a[LSW128] = a[NLSW128] = a[NMSW128] = a[MSW128] = 0;
-}
-
-/* Human-readable word order in the arguments */
-static inline void set128(unsigned int i3, unsigned int i2, unsigned int i1,
-			  unsigned int i0, int128 a)
-{
-	a[LSW128] = i0;
-	a[NLSW128] = i1;
-	a[NMSW128] = i2;
-	a[MSW128] = i3;
-}
-
-/* Convenience functions (for testing as well) */
-static inline void int64_to_128(unsigned long long src, int128 dest)
-{
-	dest[LSW128] = (unsigned int) src;
-	dest[NLSW128] = src >> 32;
-	dest[NMSW128] = dest[MSW128] = 0;
-}
-
-static inline void int128_to_64(const int128 src, unsigned long long *dest)
-{
-	*dest = src[LSW128] | (long long) src[NLSW128] << 32;
-}
-
-static inline void put_i128(const int128 a)
-{
-	printk("%08x %08x %08x %08x\n", a[MSW128], a[NMSW128],
-	       a[NLSW128], a[LSW128]);
-}
-
-/* Internal shifters:
-
-   Note that these are only good for 0 < count < 32.
- */
-
-static inline void _lsl128(unsigned int count, int128 a)
-{
-	a[MSW128] = (a[MSW128] << count) | (a[NMSW128] >> (32 - count));
-	a[NMSW128] = (a[NMSW128] << count) | (a[NLSW128] >> (32 - count));
-	a[NLSW128] = (a[NLSW128] << count) | (a[LSW128] >> (32 - count));
-	a[LSW128] <<= count;
-}
-
-static inline void _lsr128(unsigned int count, int128 a)
-{
-	a[LSW128] = (a[LSW128] >> count) | (a[NLSW128] << (32 - count));
-	a[NLSW128] = (a[NLSW128] >> count) | (a[NMSW128] << (32 - count));
-	a[NMSW128] = (a[NMSW128] >> count) | (a[MSW128] << (32 - count));
-	a[MSW128] >>= count;
-}
-
-/* Should be faster, one would hope */
-
-static inline void lslone128(int128 a)
-{
-	asm volatile ("lsl.l #1,%0\n"
-		      "roxl.l #1,%1\n"
-		      "roxl.l #1,%2\n"
-		      "roxl.l #1,%3\n"
-		      :
-		      "=d" (a[LSW128]),
-		      "=d"(a[NLSW128]),
-		      "=d"(a[NMSW128]),
-		      "=d"(a[MSW128])
-		      :
-		      "0"(a[LSW128]),
-		      "1"(a[NLSW128]),
-		      "2"(a[NMSW128]),
-		      "3"(a[MSW128]));
-}
-
-static inline void lsrone128(int128 a)
-{
-	asm volatile ("lsr.l #1,%0\n"
-		      "roxr.l #1,%1\n"
-		      "roxr.l #1,%2\n"
-		      "roxr.l #1,%3\n"
-		      :
-		      "=d" (a[MSW128]),
-		      "=d"(a[NMSW128]),
-		      "=d"(a[NLSW128]),
-		      "=d"(a[LSW128])
-		      :
-		      "0"(a[MSW128]),
-		      "1"(a[NMSW128]),
-		      "2"(a[NLSW128]),
-		      "3"(a[LSW128]));
-}
-
-/* Generalized 128-bit shifters:
-
-   These bit-shift to a multiple of 32, then move whole longwords.  */
-
-static inline void lsl128(unsigned int count, int128 a)
-{
-	int wordcount, i;
-
-	if (count % 32)
-		_lsl128(count % 32, a);
-
-	if (0 == (wordcount = count / 32))
-		return;
-
-	/* argh, gak, endian-sensitive */
-	for (i = 0; i < 4 - wordcount; i++) {
-		a[i] = a[i + wordcount];
-	}
-	for (i = 3; i >= 4 - wordcount; --i) {
-		a[i] = 0;
-	}
-}
-
-static inline void lsr128(unsigned int count, int128 a)
-{
-	int wordcount, i;
-
-	if (count % 32)
-		_lsr128(count % 32, a);
-
-	if (0 == (wordcount = count / 32))
-		return;
-
-	for (i = 3; i >= wordcount; --i) {
-		a[i] = a[i - wordcount];
-	}
-	for (i = 0; i < wordcount; i++) {
-		a[i] = 0;
-	}
-}
-
-static inline int orl128(int a, int128 b)
-{
-	b[LSW128] |= a;
-}
-
-static inline int btsthi128(const int128 a)
-{
-	return a[MSW128] & 0x80000000;
-}
-
-/* test bits (numbered from 0 = LSB) up to and including "top" */
-static inline int bftestlo128(int top, const int128 a)
-{
-	int r = 0;
-
-	if (top > 31)
-		r |= a[LSW128];
-	if (top > 63)
-		r |= a[NLSW128];
-	if (top > 95)
-		r |= a[NMSW128];
-
-	r |= a[3 - (top / 32)] & ((1 << (top % 32 + 1)) - 1);
-
-	return (r != 0);
-}
-
-/* Aargh.  We need these because GCC is broken */
-/* FIXME: do them in assembly, for goodness' sake! */
-static inline void mask64(int pos, unsigned long long *mask)
-{
-	*mask = 0;
-
-	if (pos < 32) {
-		LO_WORD(*mask) = (1 << pos) - 1;
-		return;
-	}
-	LO_WORD(*mask) = -1;
-	HI_WORD(*mask) = (1 << (pos - 32)) - 1;
-}
-
-static inline void bset64(int pos, unsigned long long *dest)
-{
-	/* This conditional will be optimized away.  Thanks, GCC! */
-	if (pos < 32)
-		asm volatile ("bset %1,%0":"=m"
-			      (LO_WORD(*dest)):"id"(pos));
-	else
-		asm volatile ("bset %1,%0":"=m"
-			      (HI_WORD(*dest)):"id"(pos - 32));
-}
-
-static inline int btst64(int pos, unsigned long long dest)
-{
-	if (pos < 32)
-		return (0 != (LO_WORD(dest) & (1 << pos)));
-	else
-		return (0 != (HI_WORD(dest) & (1 << (pos - 32))));
-}
-
-static inline void lsl64(int count, unsigned long long *dest)
-{
-	if (count < 32) {
-		HI_WORD(*dest) = (HI_WORD(*dest) << count)
-		    | (LO_WORD(*dest) >> count);
-		LO_WORD(*dest) <<= count;
-		return;
-	}
-	count -= 32;
-	HI_WORD(*dest) = LO_WORD(*dest) << count;
-	LO_WORD(*dest) = 0;
-}
-
-static inline void lsr64(int count, unsigned long long *dest)
-{
-	if (count < 32) {
-		LO_WORD(*dest) = (LO_WORD(*dest) >> count)
-		    | (HI_WORD(*dest) << (32 - count));
-		HI_WORD(*dest) >>= count;
-		return;
-	}
-	count -= 32;
-	LO_WORD(*dest) = HI_WORD(*dest) >> count;
-	HI_WORD(*dest) = 0;
-}
-#endif
-
 static inline void fp_denormalize(struct fp_ext *reg, unsigned int cnt)
 {
 	reg->exp += cnt;
@@ -481,117 +241,6 @@ static inline void fp_dividemant(union fp_mant128 *dest, struct fp_ext *src,
 	}
 }
 
-#if 0
-static inline unsigned int fp_fls128(union fp_mant128 *src)
-{
-	unsigned long data;
-	unsigned int res, off;
-
-	if ((data = src->m32[0]))
-		off = 0;
-	else if ((data = src->m32[1]))
-		off = 32;
-	else if ((data = src->m32[2]))
-		off = 64;
-	else if ((data = src->m32[3]))
-		off = 96;
-	else
-		return 128;
-
-	asm ("bfffo %1{#0,#32},%0" : "=d" (res) : "dm" (data));
-	return res + off;
-}
-
-static inline void fp_shiftmant128(union fp_mant128 *src, int shift)
-{
-	unsigned long sticky;
-
-	switch (shift) {
-	case 0:
-		return;
-	case 1:
-		asm volatile ("lsl.l #1,%0"
-			: "=d" (src->m32[3]) : "0" (src->m32[3]));
-		asm volatile ("roxl.l #1,%0"
-			: "=d" (src->m32[2]) : "0" (src->m32[2]));
-		asm volatile ("roxl.l #1,%0"
-			: "=d" (src->m32[1]) : "0" (src->m32[1]));
-		asm volatile ("roxl.l #1,%0"
-			: "=d" (src->m32[0]) : "0" (src->m32[0]));
-		return;
-	case 2 ... 31:
-		src->m32[0] = (src->m32[0] << shift) | (src->m32[1] >> (32 - shift));
-		src->m32[1] = (src->m32[1] << shift) | (src->m32[2] >> (32 - shift));
-		src->m32[2] = (src->m32[2] << shift) | (src->m32[3] >> (32 - shift));
-		src->m32[3] = (src->m32[3] << shift);
-		return;
-	case 32 ... 63:
-		shift -= 32;
-		src->m32[0] = (src->m32[1] << shift) | (src->m32[2] >> (32 - shift));
-		src->m32[1] = (src->m32[2] << shift) | (src->m32[3] >> (32 - shift));
-		src->m32[2] = (src->m32[3] << shift);
-		src->m32[3] = 0;
-		return;
-	case 64 ... 95:
-		shift -= 64;
-		src->m32[0] = (src->m32[2] << shift) | (src->m32[3] >> (32 - shift));
-		src->m32[1] = (src->m32[3] << shift);
-		src->m32[2] = src->m32[3] = 0;
-		return;
-	case 96 ... 127:
-		shift -= 96;
-		src->m32[0] = (src->m32[3] << shift);
-		src->m32[1] = src->m32[2] = src->m32[3] = 0;
-		return;
-	case -31 ... -1:
-		shift = -shift;
-		sticky = 0;
-		if (src->m32[3] << (32 - shift))
-			sticky = 1;
-		src->m32[3] = (src->m32[3] >> shift) | (src->m32[2] << (32 - shift)) | sticky;
-		src->m32[2] = (src->m32[2] >> shift) | (src->m32[1] << (32 - shift));
-		src->m32[1] = (src->m32[1] >> shift) | (src->m32[0] << (32 - shift));
-		src->m32[0] = (src->m32[0] >> shift);
-		return;
-	case -63 ... -32:
-		shift = -shift - 32;
-		sticky = 0;
-		if ((src->m32[2] << (32 - shift)) || src->m32[3])
-			sticky = 1;
-		src->m32[3] = (src->m32[2] >> shift) | (src->m32[1] << (32 - shift)) | sticky;
-		src->m32[2] = (src->m32[1] >> shift) | (src->m32[0] << (32 - shift));
-		src->m32[1] = (src->m32[0] >> shift);
-		src->m32[0] = 0;
-		return;
-	case -95 ... -64:
-		shift = -shift - 64;
-		sticky = 0;
-		if ((src->m32[1] << (32 - shift)) || src->m32[2] || src->m32[3])
-			sticky = 1;
-		src->m32[3] = (src->m32[1] >> shift) | (src->m32[0] << (32 - shift)) | sticky;
-		src->m32[2] = (src->m32[0] >> shift);
-		src->m32[1] = src->m32[0] = 0;
-		return;
-	case -127 ... -96:
-		shift = -shift - 96;
-		sticky = 0;
-		if ((src->m32[0] << (32 - shift)) || src->m32[1] || src->m32[2] || src->m32[3])
-			sticky = 1;
-		src->m32[3] = (src->m32[0] >> shift) | sticky;
-		src->m32[2] = src->m32[1] = src->m32[0] = 0;
-		return;
-	}
-
-	if (shift < 0 && (src->m32[0] || src->m32[1] || src->m32[2] || src->m32[3]))
-		src->m32[3] = 1;
-	else
-		src->m32[3] = 0;
-	src->m32[2] = 0;
-	src->m32[1] = 0;
-	src->m32[0] = 0;
-}
-#endif
-
 static inline void fp_putmant128(struct fp_ext *dest, union fp_mant128 *src,
 				 int shift)
 {
@@ -637,183 +286,4 @@ static inline void fp_putmant128(struct fp_ext *dest, union fp_mant128 *src,
 	}
 }
 
-#if 0 /* old code... */
-static inline int fls(unsigned int a)
-{
-	int r;
-
-	asm volatile ("bfffo %1{#0,#32},%0"
-		      : "=d" (r) : "md" (a));
-	return r;
-}
-
-/* fls = "find last set" (cf. ffs(3)) */
-static inline int fls128(const int128 a)
-{
-	if (a[MSW128])
-		return fls(a[MSW128]);
-	if (a[NMSW128])
-		return fls(a[NMSW128]) + 32;
-	/* XXX: it probably never gets beyond this point in actual
-	   use, but that's indicative of a more general problem in the
-	   algorithm (i.e. as per the actual 68881 implementation, we
-	   really only need at most 67 bits of precision [plus
-	   overflow]) so I'm not going to fix it. */
-	if (a[NLSW128])
-		return fls(a[NLSW128]) + 64;
-	if (a[LSW128])
-		return fls(a[LSW128]) + 96;
-	else
-		return -1;
-}
-
-static inline int zerop128(const int128 a)
-{
-	return !(a[LSW128] | a[NLSW128] | a[NMSW128] | a[MSW128]);
-}
-
-static inline int nonzerop128(const int128 a)
-{
-	return (a[LSW128] | a[NLSW128] | a[NMSW128] | a[MSW128]);
-}
-
-/* Addition and subtraction */
-/* Do these in "pure" assembly, because "extended" asm is unmanageable
-   here */
-static inline void add128(const int128 a, int128 b)
-{
-	/* rotating carry flags */
-	unsigned int carry[2];
-
-	carry[0] = a[LSW128] > (0xffffffff - b[LSW128]);
-	b[LSW128] += a[LSW128];
-
-	carry[1] = a[NLSW128] > (0xffffffff - b[NLSW128] - carry[0]);
-	b[NLSW128] = a[NLSW128] + b[NLSW128] + carry[0];
-
-	carry[0] = a[NMSW128] > (0xffffffff - b[NMSW128] - carry[1]);
-	b[NMSW128] = a[NMSW128] + b[NMSW128] + carry[1];
-
-	b[MSW128] = a[MSW128] + b[MSW128] + carry[0];
-}
-
-/* Note: assembler semantics: "b -= a" */
-static inline void sub128(const int128 a, int128 b)
-{
-	/* rotating borrow flags */
-	unsigned int borrow[2];
-
-	borrow[0] = b[LSW128] < a[LSW128];
-	b[LSW128] -= a[LSW128];
-
-	borrow[1] = b[NLSW128] < a[NLSW128] + borrow[0];
-	b[NLSW128] = b[NLSW128] - a[NLSW128] - borrow[0];
-
-	borrow[0] = b[NMSW128] < a[NMSW128] + borrow[1];
-	b[NMSW128] = b[NMSW128] - a[NMSW128] - borrow[1];
-
-	b[MSW128] = b[MSW128] - a[MSW128] - borrow[0];
-}
-
-/* Poor man's 64-bit expanding multiply */
-static inline void mul64(unsigned long long a, unsigned long long b, int128 c)
-{
-	unsigned long long acc;
-	int128 acc128;
-
-	zero128(acc128);
-	zero128(c);
-
-	/* first the low words */
-	if (LO_WORD(a) && LO_WORD(b)) {
-		acc = (long long) LO_WORD(a) * LO_WORD(b);
-		c[NLSW128] = HI_WORD(acc);
-		c[LSW128] = LO_WORD(acc);
-	}
-	/* Next the high words */
-	if (HI_WORD(a) && HI_WORD(b)) {
-		acc = (long long) HI_WORD(a) * HI_WORD(b);
-		c[MSW128] = HI_WORD(acc);
-		c[NMSW128] = LO_WORD(acc);
-	}
-	/* The middle words */
-	if (LO_WORD(a) && HI_WORD(b)) {
-		acc = (long long) LO_WORD(a) * HI_WORD(b);
-		acc128[NMSW128] = HI_WORD(acc);
-		acc128[NLSW128] = LO_WORD(acc);
-		add128(acc128, c);
-	}
-	/* The first and last words */
-	if (HI_WORD(a) && LO_WORD(b)) {
-		acc = (long long) HI_WORD(a) * LO_WORD(b);
-		acc128[NMSW128] = HI_WORD(acc);
-		acc128[NLSW128] = LO_WORD(acc);
-		add128(acc128, c);
-	}
-}
-
-/* Note: unsigned */
-static inline int cmp128(int128 a, int128 b)
-{
-	if (a[MSW128] < b[MSW128])
-		return -1;
-	if (a[MSW128] > b[MSW128])
-		return 1;
-	if (a[NMSW128] < b[NMSW128])
-		return -1;
-	if (a[NMSW128] > b[NMSW128])
-		return 1;
-	if (a[NLSW128] < b[NLSW128])
-		return -1;
-	if (a[NLSW128] > b[NLSW128])
-		return 1;
-
-	return (signed) a[LSW128] - b[LSW128];
-}
-
-inline void div128(int128 a, int128 b, int128 c)
-{
-	int128 mask;
-
-	/* Algorithm:
-
-	   Shift the divisor until it's at least as big as the
-	   dividend, keeping track of the position to which we've
-	   shifted it, i.e. the power of 2 which we've multiplied it
-	   by.
-
-	   Then, for this power of 2 (the mask), and every one smaller
-	   than it, subtract the mask from the dividend and add it to
-	   the quotient until the dividend is smaller than the raised
-	   divisor.  At this point, divide the dividend and the mask
-	   by 2 (i.e. shift one place to the right).  Lather, rinse,
-	   and repeat, until there are no more powers of 2 left. */
-
-	/* FIXME: needless to say, there's room for improvement here too. */
-
-	/* Shift up */
-	/* XXX: since it just has to be "at least as big", we can
-	   probably eliminate this horribly wasteful loop.  I will
-	   have to prove this first, though */
-	set128(0, 0, 0, 1, mask);
-	while (cmp128(b, a) < 0 && !btsthi128(b)) {
-		lslone128(b);
-		lslone128(mask);
-	}
-
-	/* Shift down */
-	zero128(c);
-	do {
-		if (cmp128(a, b) >= 0) {
-			sub128(b, a);
-			add128(mask, c);
-		}
-		lsrone128(mask);
-		lsrone128(b);
-	} while (nonzerop128(mask));
-
-	/* The remainder is in a... */
-}
-#endif
-
 #endif	/* MULTI_ARITH_H */
-- 
1.7.0.4

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