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+/* memset.S: optimised assembly memset
+ *
+ * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+
+ .text
+ .p2align 4
+
+###############################################################################
+#
+# void *memset(void *p, char ch, size_t count)
+#
+# - NOTE: must not use any stack. exception detection performs function return
+# to caller's fixup routine, aborting the remainder of the set
+# GR4, GR7, GR8, and GR11 must be managed
+#
+###############################################################################
+ .globl memset,__memset_end
+ .type memset,@function
+memset:
+ orcc.p gr10,gr0,gr5,icc3 ; GR5 = count
+ andi gr9,#0xff,gr9
+ or.p gr8,gr0,gr4 ; GR4 = address
+ beqlr icc3,#0
+
+ # conditionally write a byte to 2b-align the address
+ setlos.p #1,gr6
+ andicc gr4,#1,gr0,icc0
+ ckne icc0,cc7
+ cstb.p gr9,@(gr4,gr0) ,cc7,#1
+ csubcc gr5,gr6,gr5 ,cc7,#1 ; also set ICC3
+ cadd.p gr4,gr6,gr4 ,cc7,#1
+ beqlr icc3,#0
+
+ # conditionally write a word to 4b-align the address
+ andicc.p gr4,#2,gr0,icc0
+ subicc gr5,#2,gr0,icc1
+ setlos.p #2,gr6
+ ckne icc0,cc7
+ slli.p gr9,#8,gr12 ; need to double up the pattern
+ cknc icc1,cc5
+ or.p gr9,gr12,gr12
+ andcr cc7,cc5,cc7
+
+ csth.p gr12,@(gr4,gr0) ,cc7,#1
+ csubcc gr5,gr6,gr5 ,cc7,#1 ; also set ICC3
+ cadd.p gr4,gr6,gr4 ,cc7,#1
+ beqlr icc3,#0
+
+ # conditionally write a dword to 8b-align the address
+ andicc.p gr4,#4,gr0,icc0
+ subicc gr5,#4,gr0,icc1
+ setlos.p #4,gr6
+ ckne icc0,cc7
+ slli.p gr12,#16,gr13 ; need to quadruple-up the pattern
+ cknc icc1,cc5
+ or.p gr13,gr12,gr12
+ andcr cc7,cc5,cc7
+
+ cst.p gr12,@(gr4,gr0) ,cc7,#1
+ csubcc gr5,gr6,gr5 ,cc7,#1 ; also set ICC3
+ cadd.p gr4,gr6,gr4 ,cc7,#1
+ beqlr icc3,#0
+
+ or.p gr12,gr12,gr13 ; need to octuple-up the pattern
+
+ # the address is now 8b-aligned - loop around writing 64b chunks
+ setlos #8,gr7
+ subi.p gr4,#8,gr4 ; store with update index does weird stuff
+ setlos #64,gr6
+
+ subicc gr5,#64,gr0,icc0
+0: cknc icc0,cc7
+ cstdu gr12,@(gr4,gr7) ,cc7,#1
+ cstdu gr12,@(gr4,gr7) ,cc7,#1
+ cstdu gr12,@(gr4,gr7) ,cc7,#1
+ cstdu gr12,@(gr4,gr7) ,cc7,#1
+ cstdu gr12,@(gr4,gr7) ,cc7,#1
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ csubcc gr5,gr6,gr5 ,cc7,#1 ; also set ICC3
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ subicc gr5,#64,gr0,icc0
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ beqlr icc3,#0
+ bnc icc0,#2,0b
+
+ # now do 32-byte remnant
+ subicc.p gr5,#32,gr0,icc0
+ setlos #32,gr6
+ cknc icc0,cc7
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ csubcc gr5,gr6,gr5 ,cc7,#1 ; also set ICC3
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ setlos #16,gr6
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ subicc gr5,#16,gr0,icc0
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ beqlr icc3,#0
+
+ # now do 16-byte remnant
+ cknc icc0,cc7
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ csubcc gr5,gr6,gr5 ,cc7,#1 ; also set ICC3
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ beqlr icc3,#0
+
+ # now do 8-byte remnant
+ subicc gr5,#8,gr0,icc1
+ cknc icc1,cc7
+ cstdu.p gr12,@(gr4,gr7) ,cc7,#1
+ csubcc gr5,gr7,gr5 ,cc7,#1 ; also set ICC3
+ setlos.p #4,gr7
+ beqlr icc3,#0
+
+ # now do 4-byte remnant
+ subicc gr5,#4,gr0,icc0
+ addi.p gr4,#4,gr4
+ cknc icc0,cc7
+ cstu.p gr12,@(gr4,gr7) ,cc7,#1
+ csubcc gr5,gr7,gr5 ,cc7,#1 ; also set ICC3
+ subicc.p gr5,#2,gr0,icc1
+ beqlr icc3,#0
+
+ # now do 2-byte remnant
+ setlos #2,gr7
+ addi.p gr4,#2,gr4
+ cknc icc1,cc7
+ csthu.p gr12,@(gr4,gr7) ,cc7,#1
+ csubcc gr5,gr7,gr5 ,cc7,#1 ; also set ICC3
+ subicc.p gr5,#1,gr0,icc0
+ beqlr icc3,#0
+
+ # now do 1-byte remnant
+ setlos #0,gr7
+ addi.p gr4,#2,gr4
+ cknc icc0,cc7
+ cstb.p gr12,@(gr4,gr0) ,cc7,#1
+ bralr
+__memset_end:
+
+ .size memset, __memset_end-memset
+
+###############################################################################
+#
+# clear memory in userspace
+# - return the number of bytes that could not be cleared (0 on complete success)
+#
+# long __memset_user(void *p, size_t count)
+#
+###############################################################################
+ .globl __memset_user, __memset_user_error_lr, __memset_user_error_handler
+ .type __memset_user,@function
+__memset_user:
+ movsg lr,gr11
+
+ # abuse memset to do the dirty work
+ or.p gr9,gr9,gr10
+ setlos #0,gr9
+ call memset
+__memset_user_error_lr:
+ jmpl.p @(gr11,gr0)
+ setlos #0,gr8
+
+ # deal any exception generated by memset
+ # GR4 - memset's address tracking pointer
+ # GR7 - memset's step value (index register for store insns)
+ # GR8 - memset's original start address
+ # GR10 - memset's original count
+__memset_user_error_handler:
+ add.p gr4,gr7,gr4
+ add gr8,gr10,gr8
+ jmpl.p @(gr11,gr0)
+ sub gr8,gr4,gr8 ; we return the amount left uncleared
+
+ .size __memset_user, .-__memset_user