aboutsummaryrefslogtreecommitdiff
path: root/arch/ia64/lib/memcpy_mck.S
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/ia64/lib/memcpy_mck.S
downloadlinux-2.6.38-lt-ux500-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-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!
Diffstat (limited to 'arch/ia64/lib/memcpy_mck.S')
-rw-r--r--arch/ia64/lib/memcpy_mck.S661
1 files changed, 661 insertions, 0 deletions
diff --git a/arch/ia64/lib/memcpy_mck.S b/arch/ia64/lib/memcpy_mck.S
new file mode 100644
index 00000000000..6f26ef7cc23
--- /dev/null
+++ b/arch/ia64/lib/memcpy_mck.S
@@ -0,0 +1,661 @@
+/*
+ * Itanium 2-optimized version of memcpy and copy_user function
+ *
+ * Inputs:
+ * in0: destination address
+ * in1: source address
+ * in2: number of bytes to copy
+ * Output:
+ * 0 if success, or number of byte NOT copied if error occurred.
+ *
+ * Copyright (C) 2002 Intel Corp.
+ * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com>
+ */
+#include <linux/config.h>
+#include <asm/asmmacro.h>
+#include <asm/page.h>
+
+#define EK(y...) EX(y)
+
+/* McKinley specific optimization */
+
+#define retval r8
+#define saved_pfs r31
+#define saved_lc r10
+#define saved_pr r11
+#define saved_in0 r14
+#define saved_in1 r15
+#define saved_in2 r16
+
+#define src0 r2
+#define src1 r3
+#define dst0 r17
+#define dst1 r18
+#define cnt r9
+
+/* r19-r30 are temp for each code section */
+#define PREFETCH_DIST 8
+#define src_pre_mem r19
+#define dst_pre_mem r20
+#define src_pre_l2 r21
+#define dst_pre_l2 r22
+#define t1 r23
+#define t2 r24
+#define t3 r25
+#define t4 r26
+#define t5 t1 // alias!
+#define t6 t2 // alias!
+#define t7 t3 // alias!
+#define n8 r27
+#define t9 t5 // alias!
+#define t10 t4 // alias!
+#define t11 t7 // alias!
+#define t12 t6 // alias!
+#define t14 t10 // alias!
+#define t13 r28
+#define t15 r29
+#define tmp r30
+
+/* defines for long_copy block */
+#define A 0
+#define B (PREFETCH_DIST)
+#define C (B + PREFETCH_DIST)
+#define D (C + 1)
+#define N (D + 1)
+#define Nrot ((N + 7) & ~7)
+
+/* alias */
+#define in0 r32
+#define in1 r33
+#define in2 r34
+
+GLOBAL_ENTRY(memcpy)
+ and r28=0x7,in0
+ and r29=0x7,in1
+ mov f6=f0
+ br.cond.sptk .common_code
+ ;;
+GLOBAL_ENTRY(__copy_user)
+ .prologue
+// check dest alignment
+ and r28=0x7,in0
+ and r29=0x7,in1
+ mov f6=f1
+ mov saved_in0=in0 // save dest pointer
+ mov saved_in1=in1 // save src pointer
+ mov saved_in2=in2 // save len
+ ;;
+.common_code:
+ cmp.gt p15,p0=8,in2 // check for small size
+ cmp.ne p13,p0=0,r28 // check dest alignment
+ cmp.ne p14,p0=0,r29 // check src alignment
+ add src0=0,in1
+ sub r30=8,r28 // for .align_dest
+ mov retval=r0 // initialize return value
+ ;;
+ add dst0=0,in0
+ add dst1=1,in0 // dest odd index
+ cmp.le p6,p0 = 1,r30 // for .align_dest
+(p15) br.cond.dpnt .memcpy_short
+(p13) br.cond.dpnt .align_dest
+(p14) br.cond.dpnt .unaligned_src
+ ;;
+
+// both dest and src are aligned on 8-byte boundary
+.aligned_src:
+ .save ar.pfs, saved_pfs
+ alloc saved_pfs=ar.pfs,3,Nrot-3,0,Nrot
+ .save pr, saved_pr
+ mov saved_pr=pr
+
+ shr.u cnt=in2,7 // this much cache line
+ ;;
+ cmp.lt p6,p0=2*PREFETCH_DIST,cnt
+ cmp.lt p7,p8=1,cnt
+ .save ar.lc, saved_lc
+ mov saved_lc=ar.lc
+ .body
+ add cnt=-1,cnt
+ add src_pre_mem=0,in1 // prefetch src pointer
+ add dst_pre_mem=0,in0 // prefetch dest pointer
+ ;;
+(p7) mov ar.lc=cnt // prefetch count
+(p8) mov ar.lc=r0
+(p6) br.cond.dpnt .long_copy
+ ;;
+
+.prefetch:
+ lfetch.fault [src_pre_mem], 128
+ lfetch.fault.excl [dst_pre_mem], 128
+ br.cloop.dptk.few .prefetch
+ ;;
+
+.medium_copy:
+ and tmp=31,in2 // copy length after iteration
+ shr.u r29=in2,5 // number of 32-byte iteration
+ add dst1=8,dst0 // 2nd dest pointer
+ ;;
+ add cnt=-1,r29 // ctop iteration adjustment
+ cmp.eq p10,p0=r29,r0 // do we really need to loop?
+ add src1=8,src0 // 2nd src pointer
+ cmp.le p6,p0=8,tmp
+ ;;
+ cmp.le p7,p0=16,tmp
+ mov ar.lc=cnt // loop setup
+ cmp.eq p16,p17 = r0,r0
+ mov ar.ec=2
+(p10) br.dpnt.few .aligned_src_tail
+ ;;
+ TEXT_ALIGN(32)
+1:
+EX(.ex_handler, (p16) ld8 r34=[src0],16)
+EK(.ex_handler, (p16) ld8 r38=[src1],16)
+EX(.ex_handler, (p17) st8 [dst0]=r33,16)
+EK(.ex_handler, (p17) st8 [dst1]=r37,16)
+ ;;
+EX(.ex_handler, (p16) ld8 r32=[src0],16)
+EK(.ex_handler, (p16) ld8 r36=[src1],16)
+EX(.ex_handler, (p16) st8 [dst0]=r34,16)
+EK(.ex_handler, (p16) st8 [dst1]=r38,16)
+ br.ctop.dptk.few 1b
+ ;;
+
+.aligned_src_tail:
+EX(.ex_handler, (p6) ld8 t1=[src0])
+ mov ar.lc=saved_lc
+ mov ar.pfs=saved_pfs
+EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8)
+ cmp.le p8,p0=24,tmp
+ and r21=-8,tmp
+ ;;
+EX(.ex_hndlr_s, (p8) ld8 t3=[src1])
+EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1
+ and in2=7,tmp // remaining length
+EX(.ex_hndlr_d, (p7) st8 [dst1]=t2,8) // store byte 2
+ add src0=src0,r21 // setting up src pointer
+ add dst0=dst0,r21 // setting up dest pointer
+ ;;
+EX(.ex_handler, (p8) st8 [dst1]=t3) // store byte 3
+ mov pr=saved_pr,-1
+ br.dptk.many .memcpy_short
+ ;;
+
+/* code taken from copy_page_mck */
+.long_copy:
+ .rotr v[2*PREFETCH_DIST]
+ .rotp p[N]
+
+ mov src_pre_mem = src0
+ mov pr.rot = 0x10000
+ mov ar.ec = 1 // special unrolled loop
+
+ mov dst_pre_mem = dst0
+
+ add src_pre_l2 = 8*8, src0
+ add dst_pre_l2 = 8*8, dst0
+ ;;
+ add src0 = 8, src_pre_mem // first t1 src
+ mov ar.lc = 2*PREFETCH_DIST - 1
+ shr.u cnt=in2,7 // number of lines
+ add src1 = 3*8, src_pre_mem // first t3 src
+ add dst0 = 8, dst_pre_mem // first t1 dst
+ add dst1 = 3*8, dst_pre_mem // first t3 dst
+ ;;
+ and tmp=127,in2 // remaining bytes after this block
+ add cnt = -(2*PREFETCH_DIST) - 1, cnt
+ // same as .line_copy loop, but with all predicated-off instructions removed:
+.prefetch_loop:
+EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0
+EK(.ex_hndlr_lcpy_1, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2
+ br.ctop.sptk .prefetch_loop
+ ;;
+ cmp.eq p16, p0 = r0, r0 // reset p16 to 1
+ mov ar.lc = cnt
+ mov ar.ec = N // # of stages in pipeline
+ ;;
+.line_copy:
+EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0
+EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1
+EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory
+EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2
+ ;;
+EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory
+EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2
+EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2
+EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3
+ ;;
+EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8)
+EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8)
+EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8)
+EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8)
+ ;;
+EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8)
+EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8)
+EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8)
+EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8)
+ ;;
+EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8)
+EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8)
+EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8)
+EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8)
+ ;;
+EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8)
+EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8)
+EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8)
+EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8)
+ ;;
+EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8)
+EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8)
+EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8)
+EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8)
+ ;;
+EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8)
+EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8)
+EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8)
+EK(.ex_handler, (p[D]) st8 [dst1] = t15, 4*8)
+ br.ctop.sptk .line_copy
+ ;;
+
+ add dst0=-8,dst0
+ add src0=-8,src0
+ mov in2=tmp
+ .restore sp
+ br.sptk.many .medium_copy
+ ;;
+
+#define BLOCK_SIZE 128*32
+#define blocksize r23
+#define curlen r24
+
+// dest is on 8-byte boundary, src is not. We need to do
+// ld8-ld8, shrp, then st8. Max 8 byte copy per cycle.
+.unaligned_src:
+ .prologue
+ .save ar.pfs, saved_pfs
+ alloc saved_pfs=ar.pfs,3,5,0,8
+ .save ar.lc, saved_lc
+ mov saved_lc=ar.lc
+ .save pr, saved_pr
+ mov saved_pr=pr
+ .body
+.4k_block:
+ mov saved_in0=dst0 // need to save all input arguments
+ mov saved_in2=in2
+ mov blocksize=BLOCK_SIZE
+ ;;
+ cmp.lt p6,p7=blocksize,in2
+ mov saved_in1=src0
+ ;;
+(p6) mov in2=blocksize
+ ;;
+ shr.u r21=in2,7 // this much cache line
+ shr.u r22=in2,4 // number of 16-byte iteration
+ and curlen=15,in2 // copy length after iteration
+ and r30=7,src0 // source alignment
+ ;;
+ cmp.lt p7,p8=1,r21
+ add cnt=-1,r21
+ ;;
+
+ add src_pre_mem=0,src0 // prefetch src pointer
+ add dst_pre_mem=0,dst0 // prefetch dest pointer
+ and src0=-8,src0 // 1st src pointer
+(p7) mov ar.lc = r21
+(p8) mov ar.lc = r0
+ ;;
+ TEXT_ALIGN(32)
+1: lfetch.fault [src_pre_mem], 128
+ lfetch.fault.excl [dst_pre_mem], 128
+ br.cloop.dptk.few 1b
+ ;;
+
+ shladd dst1=r22,3,dst0 // 2nd dest pointer
+ shladd src1=r22,3,src0 // 2nd src pointer
+ cmp.eq p8,p9=r22,r0 // do we really need to loop?
+ cmp.le p6,p7=8,curlen; // have at least 8 byte remaining?
+ add cnt=-1,r22 // ctop iteration adjustment
+ ;;
+EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer
+EK(.ex_handler, (p9) ld8 r37=[src1],8)
+(p8) br.dpnt.few .noloop
+ ;;
+
+// The jump address is calculated based on src alignment. The COPYU
+// macro below need to confine its size to power of two, so an entry
+// can be caulated using shl instead of an expensive multiply. The
+// size is then hard coded by the following #define to match the
+// actual size. This make it somewhat tedious when COPYU macro gets
+// changed and this need to be adjusted to match.
+#define LOOP_SIZE 6
+1:
+ mov r29=ip // jmp_table thread
+ mov ar.lc=cnt
+ ;;
+ add r29=.jump_table - 1b - (.jmp1-.jump_table), r29
+ shl r28=r30, LOOP_SIZE // jmp_table thread
+ mov ar.ec=2 // loop setup
+ ;;
+ add r29=r29,r28 // jmp_table thread
+ cmp.eq p16,p17=r0,r0
+ ;;
+ mov b6=r29 // jmp_table thread
+ ;;
+ br.cond.sptk.few b6
+
+// for 8-15 byte case
+// We will skip the loop, but need to replicate the side effect
+// that the loop produces.
+.noloop:
+EX(.ex_handler, (p6) ld8 r37=[src1],8)
+ add src0=8,src0
+(p6) shl r25=r30,3
+ ;;
+EX(.ex_handler, (p6) ld8 r27=[src1])
+(p6) shr.u r28=r37,r25
+(p6) sub r26=64,r25
+ ;;
+(p6) shl r27=r27,r26
+ ;;
+(p6) or r21=r28,r27
+
+.unaligned_src_tail:
+/* check if we have more than blocksize to copy, if so go back */
+ cmp.gt p8,p0=saved_in2,blocksize
+ ;;
+(p8) add dst0=saved_in0,blocksize
+(p8) add src0=saved_in1,blocksize
+(p8) sub in2=saved_in2,blocksize
+(p8) br.dpnt .4k_block
+ ;;
+
+/* we have up to 15 byte to copy in the tail.
+ * part of work is already done in the jump table code
+ * we are at the following state.
+ * src side:
+ *
+ * xxxxxx xx <----- r21 has xxxxxxxx already
+ * -------- -------- --------
+ * 0 8 16
+ * ^
+ * |
+ * src1
+ *
+ * dst
+ * -------- -------- --------
+ * ^
+ * |
+ * dst1
+ */
+EX(.ex_handler, (p6) st8 [dst1]=r21,8) // more than 8 byte to copy
+(p6) add curlen=-8,curlen // update length
+ mov ar.pfs=saved_pfs
+ ;;
+ mov ar.lc=saved_lc
+ mov pr=saved_pr,-1
+ mov in2=curlen // remaining length
+ mov dst0=dst1 // dest pointer
+ add src0=src1,r30 // forward by src alignment
+ ;;
+
+// 7 byte or smaller.
+.memcpy_short:
+ cmp.le p8,p9 = 1,in2
+ cmp.le p10,p11 = 2,in2
+ cmp.le p12,p13 = 3,in2
+ cmp.le p14,p15 = 4,in2
+ add src1=1,src0 // second src pointer
+ add dst1=1,dst0 // second dest pointer
+ ;;
+
+EX(.ex_handler_short, (p8) ld1 t1=[src0],2)
+EK(.ex_handler_short, (p10) ld1 t2=[src1],2)
+(p9) br.ret.dpnt rp // 0 byte copy
+ ;;
+
+EX(.ex_handler_short, (p8) st1 [dst0]=t1,2)
+EK(.ex_handler_short, (p10) st1 [dst1]=t2,2)
+(p11) br.ret.dpnt rp // 1 byte copy
+
+EX(.ex_handler_short, (p12) ld1 t3=[src0],2)
+EK(.ex_handler_short, (p14) ld1 t4=[src1],2)
+(p13) br.ret.dpnt rp // 2 byte copy
+ ;;
+
+ cmp.le p6,p7 = 5,in2
+ cmp.le p8,p9 = 6,in2
+ cmp.le p10,p11 = 7,in2
+
+EX(.ex_handler_short, (p12) st1 [dst0]=t3,2)
+EK(.ex_handler_short, (p14) st1 [dst1]=t4,2)
+(p15) br.ret.dpnt rp // 3 byte copy
+ ;;
+
+EX(.ex_handler_short, (p6) ld1 t5=[src0],2)
+EK(.ex_handler_short, (p8) ld1 t6=[src1],2)
+(p7) br.ret.dpnt rp // 4 byte copy
+ ;;
+
+EX(.ex_handler_short, (p6) st1 [dst0]=t5,2)
+EK(.ex_handler_short, (p8) st1 [dst1]=t6,2)
+(p9) br.ret.dptk rp // 5 byte copy
+
+EX(.ex_handler_short, (p10) ld1 t7=[src0],2)
+(p11) br.ret.dptk rp // 6 byte copy
+ ;;
+
+EX(.ex_handler_short, (p10) st1 [dst0]=t7,2)
+ br.ret.dptk rp // done all cases
+
+
+/* Align dest to nearest 8-byte boundary. We know we have at
+ * least 7 bytes to copy, enough to crawl to 8-byte boundary.
+ * Actual number of byte to crawl depend on the dest alignment.
+ * 7 byte or less is taken care at .memcpy_short
+
+ * src0 - source even index
+ * src1 - source odd index
+ * dst0 - dest even index
+ * dst1 - dest odd index
+ * r30 - distance to 8-byte boundary
+ */
+
+.align_dest:
+ add src1=1,in1 // source odd index
+ cmp.le p7,p0 = 2,r30 // for .align_dest
+ cmp.le p8,p0 = 3,r30 // for .align_dest
+EX(.ex_handler_short, (p6) ld1 t1=[src0],2)
+ cmp.le p9,p0 = 4,r30 // for .align_dest
+ cmp.le p10,p0 = 5,r30
+ ;;
+EX(.ex_handler_short, (p7) ld1 t2=[src1],2)
+EK(.ex_handler_short, (p8) ld1 t3=[src0],2)
+ cmp.le p11,p0 = 6,r30
+EX(.ex_handler_short, (p6) st1 [dst0] = t1,2)
+ cmp.le p12,p0 = 7,r30
+ ;;
+EX(.ex_handler_short, (p9) ld1 t4=[src1],2)
+EK(.ex_handler_short, (p10) ld1 t5=[src0],2)
+EX(.ex_handler_short, (p7) st1 [dst1] = t2,2)
+EK(.ex_handler_short, (p8) st1 [dst0] = t3,2)
+ ;;
+EX(.ex_handler_short, (p11) ld1 t6=[src1],2)
+EK(.ex_handler_short, (p12) ld1 t7=[src0],2)
+ cmp.eq p6,p7=r28,r29
+EX(.ex_handler_short, (p9) st1 [dst1] = t4,2)
+EK(.ex_handler_short, (p10) st1 [dst0] = t5,2)
+ sub in2=in2,r30
+ ;;
+EX(.ex_handler_short, (p11) st1 [dst1] = t6,2)
+EK(.ex_handler_short, (p12) st1 [dst0] = t7)
+ add dst0=in0,r30 // setup arguments
+ add src0=in1,r30
+(p6) br.cond.dptk .aligned_src
+(p7) br.cond.dpnt .unaligned_src
+ ;;
+
+/* main loop body in jump table format */
+#define COPYU(shift) \
+1: \
+EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \
+EK(.ex_handler, (p16) ld8 r36=[src1],8); \
+ (p17) shrp r35=r33,r34,shift;; /* 1 */ \
+EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \
+ nop.m 0; \
+ (p16) shrp r38=r36,r37,shift; \
+EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \
+EK(.ex_handler, (p17) st8 [dst1]=r39,8); \
+ br.ctop.dptk.few 1b;; \
+ (p7) add src1=-8,src1; /* back out for <8 byte case */ \
+ shrp r21=r22,r38,shift; /* speculative work */ \
+ br.sptk.few .unaligned_src_tail /* branch out of jump table */ \
+ ;;
+ TEXT_ALIGN(32)
+.jump_table:
+ COPYU(8) // unaligned cases
+.jmp1:
+ COPYU(16)
+ COPYU(24)
+ COPYU(32)
+ COPYU(40)
+ COPYU(48)
+ COPYU(56)
+
+#undef A
+#undef B
+#undef C
+#undef D
+END(memcpy)
+
+/*
+ * Due to lack of local tag support in gcc 2.x assembler, it is not clear which
+ * instruction failed in the bundle. The exception algorithm is that we
+ * first figure out the faulting address, then detect if there is any
+ * progress made on the copy, if so, redo the copy from last known copied
+ * location up to the faulting address (exclusive). In the copy_from_user
+ * case, remaining byte in kernel buffer will be zeroed.
+ *
+ * Take copy_from_user as an example, in the code there are multiple loads
+ * in a bundle and those multiple loads could span over two pages, the
+ * faulting address is calculated as page_round_down(max(src0, src1)).
+ * This is based on knowledge that if we can access one byte in a page, we
+ * can access any byte in that page.
+ *
+ * predicate used in the exception handler:
+ * p6-p7: direction
+ * p10-p11: src faulting addr calculation
+ * p12-p13: dst faulting addr calculation
+ */
+
+#define A r19
+#define B r20
+#define C r21
+#define D r22
+#define F r28
+
+#define memset_arg0 r32
+#define memset_arg2 r33
+
+#define saved_retval loc0
+#define saved_rtlink loc1
+#define saved_pfs_stack loc2
+
+.ex_hndlr_s:
+ add src0=8,src0
+ br.sptk .ex_handler
+ ;;
+.ex_hndlr_d:
+ add dst0=8,dst0
+ br.sptk .ex_handler
+ ;;
+.ex_hndlr_lcpy_1:
+ mov src1=src_pre_mem
+ mov dst1=dst_pre_mem
+ cmp.gtu p10,p11=src_pre_mem,saved_in1
+ cmp.gtu p12,p13=dst_pre_mem,saved_in0
+ ;;
+(p10) add src0=8,saved_in1
+(p11) mov src0=saved_in1
+(p12) add dst0=8,saved_in0
+(p13) mov dst0=saved_in0
+ br.sptk .ex_handler
+.ex_handler_lcpy:
+ // in line_copy block, the preload addresses should always ahead
+ // of the other two src/dst pointers. Furthermore, src1/dst1 should
+ // always ahead of src0/dst0.
+ mov src1=src_pre_mem
+ mov dst1=dst_pre_mem
+.ex_handler:
+ mov pr=saved_pr,-1 // first restore pr, lc, and pfs
+ mov ar.lc=saved_lc
+ mov ar.pfs=saved_pfs
+ ;;
+.ex_handler_short: // fault occurred in these sections didn't change pr, lc, pfs
+ cmp.ltu p6,p7=saved_in0, saved_in1 // get the copy direction
+ cmp.ltu p10,p11=src0,src1
+ cmp.ltu p12,p13=dst0,dst1
+ fcmp.eq p8,p0=f6,f0 // is it memcpy?
+ mov tmp = dst0
+ ;;
+(p11) mov src1 = src0 // pick the larger of the two
+(p13) mov dst0 = dst1 // make dst0 the smaller one
+(p13) mov dst1 = tmp // and dst1 the larger one
+ ;;
+(p6) dep F = r0,dst1,0,PAGE_SHIFT // usr dst round down to page boundary
+(p7) dep F = r0,src1,0,PAGE_SHIFT // usr src round down to page boundary
+ ;;
+(p6) cmp.le p14,p0=dst0,saved_in0 // no progress has been made on store
+(p7) cmp.le p14,p0=src0,saved_in1 // no progress has been made on load
+ mov retval=saved_in2
+(p8) ld1 tmp=[src1] // force an oops for memcpy call
+(p8) st1 [dst1]=r0 // force an oops for memcpy call
+(p14) br.ret.sptk.many rp
+
+/*
+ * The remaining byte to copy is calculated as:
+ *
+ * A = (faulting_addr - orig_src) -> len to faulting ld address
+ * or
+ * (faulting_addr - orig_dst) -> len to faulting st address
+ * B = (cur_dst - orig_dst) -> len copied so far
+ * C = A - B -> len need to be copied
+ * D = orig_len - A -> len need to be zeroed
+ */
+(p6) sub A = F, saved_in0
+(p7) sub A = F, saved_in1
+ clrrrb
+ ;;
+ alloc saved_pfs_stack=ar.pfs,3,3,3,0
+ sub B = dst0, saved_in0 // how many byte copied so far
+ ;;
+ sub C = A, B
+ sub D = saved_in2, A
+ ;;
+ cmp.gt p8,p0=C,r0 // more than 1 byte?
+ add memset_arg0=saved_in0, A
+(p6) mov memset_arg2=0 // copy_to_user should not call memset
+(p7) mov memset_arg2=D // copy_from_user need to have kbuf zeroed
+ mov r8=0
+ mov saved_retval = D
+ mov saved_rtlink = b0
+
+ add out0=saved_in0, B
+ add out1=saved_in1, B
+ mov out2=C
+(p8) br.call.sptk.few b0=__copy_user // recursive call
+ ;;
+
+ add saved_retval=saved_retval,r8 // above might return non-zero value
+ cmp.gt p8,p0=memset_arg2,r0 // more than 1 byte?
+ mov out0=memset_arg0 // *s
+ mov out1=r0 // c
+ mov out2=memset_arg2 // n
+(p8) br.call.sptk.few b0=memset
+ ;;
+
+ mov retval=saved_retval
+ mov ar.pfs=saved_pfs_stack
+ mov b0=saved_rtlink
+ br.ret.sptk.many rp
+
+/* end of McKinley specific optimization */
+END(__copy_user)