summaryrefslogtreecommitdiffstats
path: root/arch/s390/lib/mem64.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/s390/lib/mem64.S')
-rw-r--r--arch/s390/lib/mem64.S88
1 files changed, 88 insertions, 0 deletions
diff --git a/arch/s390/lib/mem64.S b/arch/s390/lib/mem64.S
new file mode 100644
index 00000000000..c6d553e85ab
--- /dev/null
+++ b/arch/s390/lib/mem64.S
@@ -0,0 +1,88 @@
+/*
+ * String handling functions.
+ *
+ * Copyright IBM Corp. 2012
+ */
+
+#include <linux/linkage.h>
+
+/*
+ * memset implementation
+ *
+ * This code corresponds to the C construct below. We do distinguish
+ * between clearing (c == 0) and setting a memory array (c != 0) simply
+ * because nearly all memset invocations in the kernel clear memory and
+ * the xc instruction is preferred in such cases.
+ *
+ * void *memset(void *s, int c, size_t n)
+ * {
+ * if (likely(c == 0))
+ * return __builtin_memset(s, 0, n);
+ * return __builtin_memset(s, c, n);
+ * }
+ */
+ENTRY(memset)
+ ltgr %r4,%r4
+ bzr %r14
+ ltgr %r3,%r3
+ jnz .Lmemset_fill
+ aghi %r4,-1
+ srlg %r3,%r4,8
+ ltgr %r3,%r3
+ lgr %r1,%r2
+ jz .Lmemset_clear_rest
+.Lmemset_clear_loop:
+ xc 0(256,%r1),0(%r1)
+ la %r1,256(%r1)
+ brctg %r3,.Lmemset_clear_loop
+.Lmemset_clear_rest:
+ larl %r3,.Lmemset_xc
+ ex %r4,0(%r3)
+ br %r14
+.Lmemset_fill:
+ stc %r3,0(%r2)
+ cghi %r4,1
+ lgr %r1,%r2
+ ber %r14
+ aghi %r4,-2
+ srlg %r3,%r4,8
+ ltgr %r3,%r3
+ jz .Lmemset_fill_rest
+.Lmemset_fill_loop:
+ mvc 1(256,%r1),0(%r1)
+ la %r1,256(%r1)
+ brctg %r3,.Lmemset_fill_loop
+.Lmemset_fill_rest:
+ larl %r3,.Lmemset_mvc
+ ex %r4,0(%r3)
+ br %r14
+.Lmemset_xc:
+ xc 0(1,%r1),0(%r1)
+.Lmemset_mvc:
+ mvc 1(1,%r1),0(%r1)
+
+/*
+ * memcpy implementation
+ *
+ * void *memcpy(void *dest, const void *src, size_t n)
+ */
+ENTRY(memcpy)
+ ltgr %r4,%r4
+ bzr %r14
+ aghi %r4,-1
+ srlg %r5,%r4,8
+ ltgr %r5,%r5
+ lgr %r1,%r2
+ jnz .Lmemcpy_loop
+.Lmemcpy_rest:
+ larl %r5,.Lmemcpy_mvc
+ ex %r4,0(%r5)
+ br %r14
+.Lmemcpy_loop:
+ mvc 0(256,%r1),0(%r3)
+ la %r1,256(%r1)
+ la %r3,256(%r3)
+ brctg %r5,.Lmemcpy_loop
+ j .Lmemcpy_rest
+.Lmemcpy_mvc:
+ mvc 0(1,%r1),0(%r3)