Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 248 insertions, 0 deletions

diff --git a/arch/alpha/lib/ev6-memcpy.S b/arch/alpha/lib/ev6-memcpy.S
new file mode 100644
index 0000000..52b37b0
--- /dev/null
+++ b/arch/alpha/lib/ev6-memcpy.S
@@ -0,0 +1,248 @@
+/*
+ * arch/alpha/lib/ev6-memcpy.S
+ * 21264 version by Rick Gorton <rick.gorton@alpha-processor.com>
+ *
+ * Reasonably optimized memcpy() routine for the Alpha 21264
+ *
+ *	- memory accessed as aligned quadwords only
+ *	- uses bcmpge to compare 8 bytes in parallel
+ *
+ * Much of the information about 21264 scheduling/coding comes from:
+ *	Compiler Writer's Guide for the Alpha 21264
+ *	abbreviated as 'CWG' in other comments here
+ *	ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html
+ * Scheduling notation:
+ *	E	- either cluster
+ *	U	- upper subcluster; U0 - subcluster U0; U1 - subcluster U1
+ *	L	- lower subcluster; L0 - subcluster L0; L1 - subcluster L1
+ *
+ * Temp usage notes:
+ *	$1,$2,		- scratch
+ */
+
+	.set noreorder
+	.set noat
+
+	.align	4
+	.globl memcpy
+	.ent memcpy
+memcpy:
+	.frame $30,0,$26,0
+	.prologue 0
+
+	mov	$16, $0			# E : copy dest to return
+	ble	$18, $nomoredata	# U : done with the copy?
+	xor	$16, $17, $1		# E : are source and dest alignments the same?
+	and	$1, 7, $1		# E : are they the same mod 8?
+
+	bne	$1, $misaligned		# U : Nope - gotta do this the slow way
+	/* source and dest are same mod 8 address */
+	and	$16, 7, $1		# E : Are both 0mod8?
+	beq	$1, $both_0mod8		# U : Yes
+	nop				# E :
+
+	/*
+	 * source and dest are same misalignment.  move a byte at a time
+	 * until a 0mod8 alignment for both is reached.
+	 * At least one byte more to move
+	 */
+
+$head_align:
+	ldbu	$1, 0($17)		# L : grab a byte
+	subq	$18, 1, $18		# E : count--
+	addq	$17, 1, $17		# E : src++
+	stb	$1, 0($16)		# L :
+	addq	$16, 1, $16		# E : dest++
+	and	$16, 7, $1		# E : Are we at 0mod8 yet?
+	ble	$18, $nomoredata	# U : done with the copy?
+	bne	$1, $head_align		# U :
+
+$both_0mod8:
+	cmple	$18, 127, $1		# E : Can we unroll the loop?
+	bne	$1, $no_unroll		# U :
+	and	$16, 63, $1		# E : get mod64 alignment
+	beq	$1, $do_unroll		# U : no single quads to fiddle
+
+$single_head_quad:
+	ldq	$1, 0($17)		# L : get 8 bytes
+	subq	$18, 8, $18		# E : count -= 8
+	addq	$17, 8, $17		# E : src += 8
+	nop				# E :
+
+	stq	$1, 0($16)		# L : store
+	addq	$16, 8, $16		# E : dest += 8
+	and	$16, 63, $1		# E : get mod64 alignment
+	bne	$1, $single_head_quad	# U : still not fully aligned
+
+$do_unroll:
+	addq	$16, 64, $7		# E : Initial (+1 trip) wh64 address
+	cmple	$18, 127, $1		# E : Can we go through the unrolled loop?
+	bne	$1, $tail_quads		# U : Nope
+	nop				# E : 
+
+$unroll_body:
+	wh64	($7)			# L1 : memory subsystem hint: 64 bytes at
+					# ($7) are about to be over-written
+	ldq	$6, 0($17)		# L0 : bytes 0..7
+	nop				# E :
+	nop				# E :
+
+	ldq	$4, 8($17)		# L : bytes 8..15
+	ldq	$5, 16($17)		# L : bytes 16..23
+	addq	$7, 64, $7		# E : Update next wh64 address
+	nop				# E :
+
+	ldq	$3, 24($17)		# L : bytes 24..31
+	addq	$16, 64, $1		# E : fallback value for wh64
+	nop				# E :
+	nop				# E :
+
+	addq	$17, 32, $17		# E : src += 32 bytes
+	stq	$6, 0($16)		# L : bytes 0..7
+	nop				# E :
+	nop				# E :
+
+	stq	$4, 8($16)		# L : bytes 8..15
+	stq	$5, 16($16)		# L : bytes 16..23
+	subq	$18, 192, $2		# E : At least two more trips to go?
+	nop				# E :
+
+	stq	$3, 24($16)		# L : bytes 24..31
+	addq	$16, 32, $16		# E : dest += 32 bytes
+	nop				# E :
+	nop				# E :
+
+	ldq	$6, 0($17)		# L : bytes 0..7
+	ldq	$4, 8($17)		# L : bytes 8..15
+	cmovlt	$2, $1, $7		# E : Latency 2, extra map slot - Use
+					# fallback wh64 address if < 2 more trips
+	nop				# E :
+
+	ldq	$5, 16($17)		# L : bytes 16..23
+	ldq	$3, 24($17)		# L : bytes 24..31
+	addq	$16, 32, $16		# E : dest += 32
+	subq	$18, 64, $18		# E : count -= 64
+
+	addq	$17, 32, $17		# E : src += 32
+	stq	$6, -32($16)		# L : bytes 0..7
+	stq	$4, -24($16)		# L : bytes 8..15
+	cmple	$18, 63, $1		# E : At least one more trip?
+
+	stq	$5, -16($16)		# L : bytes 16..23
+	stq	$3, -8($16)		# L : bytes 24..31
+	nop				# E :
+	beq	$1, $unroll_body
+
+$tail_quads:
+$no_unroll:
+	.align 4
+	subq	$18, 8, $18		# E : At least a quad left?
+	blt	$18, $less_than_8	# U : Nope
+	nop				# E :
+	nop				# E :
+
+$move_a_quad:
+	ldq	$1, 0($17)		# L : fetch 8
+	subq	$18, 8, $18		# E : count -= 8
+	addq	$17, 8, $17		# E : src += 8
+	nop				# E :
+
+	stq	$1, 0($16)		# L : store 8
+	addq	$16, 8, $16		# E : dest += 8
+	bge	$18, $move_a_quad	# U :
+	nop				# E :
+
+$less_than_8:
+	.align 4
+	addq	$18, 8, $18		# E : add back for trailing bytes
+	ble	$18, $nomoredata	# U : All-done
+	nop				# E :
+	nop				# E :
+
+	/* Trailing bytes */
+$tail_bytes:
+	subq	$18, 1, $18		# E : count--
+	ldbu	$1, 0($17)		# L : fetch a byte
+	addq	$17, 1, $17		# E : src++
+	nop				# E :
+
+	stb	$1, 0($16)		# L : store a byte
+	addq	$16, 1, $16		# E : dest++
+	bgt	$18, $tail_bytes	# U : more to be done?
+	nop				# E :
+
+	/* branching to exit takes 3 extra cycles, so replicate exit here */
+	ret	$31, ($26), 1		# L0 :
+	nop				# E :
+	nop				# E :
+	nop				# E :
+
+$misaligned:
+	mov	$0, $4			# E : dest temp
+	and	$0, 7, $1		# E : dest alignment mod8
+	beq	$1, $dest_0mod8		# U : life doesnt totally suck
+	nop
+
+$aligndest:
+	ble	$18, $nomoredata	# U :
+	ldbu	$1, 0($17)		# L : fetch a byte
+	subq	$18, 1, $18		# E : count--
+	addq	$17, 1, $17		# E : src++
+
+	stb	$1, 0($4)		# L : store it
+	addq	$4, 1, $4		# E : dest++
+	and	$4, 7, $1		# E : dest 0mod8 yet?
+	bne	$1, $aligndest		# U : go until we are aligned.
+
+	/* Source has unknown alignment, but dest is known to be 0mod8 */
+$dest_0mod8:
+	subq	$18, 8, $18		# E : At least a quad left?
+	blt	$18, $misalign_tail	# U : Nope
+	ldq_u	$3, 0($17)		# L : seed (rotating load) of 8 bytes
+	nop				# E :
+
+$mis_quad:
+	ldq_u	$16, 8($17)		# L : Fetch next 8
+	extql	$3, $17, $3		# U : masking
+	extqh	$16, $17, $1		# U : masking
+	bis	$3, $1, $1		# E : merged bytes to store
+
+	subq	$18, 8, $18		# E : count -= 8
+	addq	$17, 8, $17		# E : src += 8
+	stq	$1, 0($4)		# L : store 8 (aligned)
+	mov	$16, $3			# E : "rotate" source data
+
+	addq	$4, 8, $4		# E : dest += 8
+	bge	$18, $mis_quad		# U : More quads to move
+	nop
+	nop
+
+$misalign_tail:
+	addq	$18, 8, $18		# E : account for tail stuff
+	ble	$18, $nomoredata	# U :
+	nop
+	nop
+
+$misalign_byte:
+	ldbu	$1, 0($17)		# L : fetch 1
+	subq	$18, 1, $18		# E : count--
+	addq	$17, 1, $17		# E : src++
+	nop				# E :
+
+	stb	$1, 0($4)		# L : store
+	addq	$4, 1, $4		# E : dest++
+	bgt	$18, $misalign_byte	# U : more to go?
+	nop
+
+
+$nomoredata:
+	ret	$31, ($26), 1		# L0 :
+	nop				# E :
+	nop				# E :
+	nop				# E :
+
+	.end memcpy
+
+/* For backwards module compatibility.  */
+__memcpy = memcpy
+.globl __memcpy