patch-2.4.22 linux-2.4.22/arch/sh64/lib/copy_user_memcpy.S

• Lines: 212
• Date: 2003-08-25 04:44:40.000000000 -0700
• Orig file: linux-2.4.21/arch/sh64/lib/copy_user_memcpy.S
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.21/arch/sh64/lib/copy_user_memcpy.S linux-2.4.22/arch/sh64/lib/copy_user_memcpy.S
@@ -0,0 +1,211 @@
+!
+! Fast SH memcpy
+!
+! by Toshiyasu Morita (tm@netcom.com)
+! hacked by J"orn Rernnecke (joern.rennecke@superh.com) ("o for o-umlaut)
+! SH5 code Copyright 2002 SuperH Ltd.
+!
+! Entry: ARG0: destination pointer
+!        ARG1: source pointer
+!        ARG2: byte count
+!
+! Exit:  RESULT: destination pointer
+!        any other registers in the range r0-r7: trashed
+!
+! Notes: Usually one wants to do small reads and write a longword, but
+!        unfortunately it is difficult in some cases to concatanate bytes
+!        into a longword on the SH, so this does a longword read and small
+!        writes.
+!
+! This implementation makes two assumptions about how it is called:
+!
+! 1.: If the byte count is nonzero, the address of the last byte to be
+!     copied is unsigned greater than the address of the first byte to
+!     be copied.  This could be easily swapped for a signed comparison,
+!     but the algorithm used needs some comparison.
+!
+! 2.: When there are two or three bytes in the last word of an 11-or-more
+!     bytes memory chunk to b copied, the rest of the word can be read
+!     without side effects.
+!     This could be easily changed by increasing the minumum size of
+!     a fast memcpy and the amount subtracted from r7 before L_2l_loop be 2,
+!     however, this would cost a few extra cyles on average.
+!     For SHmedia, the assumption is that any quadword can be read in its
+!     enirety if at least one byte is included in the copy.
+
+/* Imported into Linux kernel by Richard Curnow.  This is used to implement the
+   __copy_user function in the general case, so it has to be a distinct
+   function from intra-kernel memcpy to allow for exception fix-ups in the
+   event that the user pointer is bad somewhere in the copy (e.g. due to
+   running off the end of the vma).
+
+   Note, this algorithm will be slightly wasteful in the case where the source
+   and destination pointers are equally aligned, because the stlo/sthi pairs
+   could then be merged back into single stores.  If there are a lot of cache
+   misses, this is probably offset by the stall lengths on the preloads.
+
+*/
+
+	.section .text..SHmedia32,"ax"
+	.little
+	.balign 32
+	.global copy_user_memcpy
+	.global copy_user_memcpy_end
+copy_user_memcpy:
+
+#define LDUAQ(P,O,D0,D1) ldlo.q P,O,D0; ldhi.q P,O+7,D1
+#define STUAQ(P,O,D0,D1) stlo.q P,O,D0; sthi.q P,O+7,D1
+#define LDUAL(P,O,D0,D1) ldlo.l P,O,D0; ldhi.l P,O+3,D1
+#define STUAL(P,O,D0,D1) stlo.l P,O,D0; sthi.l P,O+3,D1
+
+	ld.b r3,0,r63
+	pta/l Large,tr0
+	movi 25,r0
+	bgeu/u r4,r0,tr0
+	nsb r4,r0
+	shlli r0,5,r0
+	movi (L1-L0+63*32 + 1) & 0xffff,r1
+	sub r1, r0, r0
+L0:	ptrel r0,tr0
+	add r2,r4,r5
+	ptabs r18,tr1
+	add r3,r4,r6
+	blink tr0,r63
+
+/* Rearranged to make cut2 safe */
+	.balign 8
+L4_7:	/* 4..7 byte memcpy cntd. */
+	stlo.l r2, 0, r0
+	or r6, r7, r6
+	sthi.l r5, -1, r6
+	stlo.l r5, -4, r6
+	blink tr1,r63
+
+	.balign 8
+L1:	/* 0 byte memcpy */
+	nop
+	blink tr1,r63
+	nop
+	nop
+	nop
+	nop
+
+L2_3:	/* 2 or 3 byte memcpy cntd. */
+	st.b r5,-1,r6
+	blink tr1,r63
+
+	/* 1 byte memcpy */
+	ld.b r3,0,r0
+	st.b r2,0,r0
+	blink tr1,r63
+
+L8_15:	/* 8..15 byte memcpy cntd. */
+	stlo.q r2, 0, r0
+	or r6, r7, r6
+	sthi.q r5, -1, r6
+	stlo.q r5, -8, r6
+	blink tr1,r63
+	
+	/* 2 or 3 byte memcpy */
+	ld.b r3,0,r0
+	ld.b r2,0,r63
+	ld.b r3,1,r1
+	st.b r2,0,r0
+	pta/l L2_3,tr0
+	ld.b r6,-1,r6
+	st.b r2,1,r1
+	blink tr0, r63
+
+	/* 4 .. 7 byte memcpy */
+	LDUAL (r3, 0, r0, r1)
+	pta L4_7, tr0
+	ldlo.l r6, -4, r7
+	or r0, r1, r0
+	sthi.l r2, 3, r0
+	ldhi.l r6, -1, r6
+	blink tr0, r63
+
+	/* 8 .. 15 byte memcpy */
+	LDUAQ (r3, 0, r0, r1)
+	pta L8_15, tr0
+	ldlo.q r6, -8, r7
+	or r0, r1, r0
+	sthi.q r2, 7, r0
+	ldhi.q r6, -1, r6
+	blink tr0, r63
+
+	/* 16 .. 24 byte memcpy */
+	LDUAQ (r3, 0, r0, r1)
+	LDUAQ (r3, 8, r8, r9)
+	or r0, r1, r0
+	sthi.q r2, 7, r0
+	or r8, r9, r8
+	sthi.q r2, 15, r8
+	ldlo.q r6, -8, r7
+	ldhi.q r6, -1, r6
+	stlo.q r2, 8, r8
+	stlo.q r2, 0, r0
+	or r6, r7, r6
+	sthi.q r5, -1, r6
+	stlo.q r5, -8, r6
+	blink tr1,r63
+
+Large:
+	ld.b r2, 0, r63
+	pta/l  Loop_ua, tr1
+	ori r3, -8, r7
+	sub r2, r7, r22
+	sub r3, r2, r6
+	add r2, r4, r5
+	ldlo.q r3, 0, r0
+	addi r5, -16, r5
+	movi 64+8, r27 ! could subtract r7 from that.
+	stlo.q r2, 0, r0
+	sthi.q r2, 7, r0
+	ldx.q r22, r6, r0
+	bgtu/l r27, r4, tr1
+
+	addi r5, -48, r27
+	pta/l Loop_line, tr0
+	addi r6, 64, r36
+	addi r6, -24, r19
+	addi r6, -16, r20
+	addi r6, -8, r21
+
+Loop_line:
+	ldx.q r22, r36, r63
+	alloco r22, 32
+	addi r22, 32, r22
+	ldx.q r22, r19, r23
+	sthi.q r22, -25, r0
+	ldx.q r22, r20, r24
+	ldx.q r22, r21, r25
+	stlo.q r22, -32, r0
+	ldx.q r22, r6,  r0
+	sthi.q r22, -17, r23
+	sthi.q r22,  -9, r24
+	sthi.q r22,  -1, r25
+	stlo.q r22, -24, r23
+	stlo.q r22, -16, r24
+	stlo.q r22,  -8, r25
+	bgeu r27, r22, tr0
+
+Loop_ua:
+	addi r22, 8, r22
+	sthi.q r22, -1, r0
+	stlo.q r22, -8, r0
+	ldx.q r22, r6, r0
+	bgtu/l r5, r22, tr1
+
+	add r3, r4, r7
+	ldlo.q r7, -8, r1
+	sthi.q r22, 7, r0
+	ldhi.q r7, -1, r7
+	ptabs r18,tr1
+	stlo.q r22, 0, r0
+	or r1, r7, r1
+	sthi.q r5, 15, r1
+	stlo.q r5, 8, r1
+	blink tr1, r63
+copy_user_memcpy_end:
+	nop