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-rw-r--r--libkern/memset-386.s35
1 files changed, 35 insertions, 0 deletions
diff --git a/libkern/memset-386.s b/libkern/memset-386.s
new file mode 100644
index 00000000..dacb2f5f
--- /dev/null
+++ b/libkern/memset-386.s
@@ -0,0 +1,35 @@
+ TEXT memset(SB),$0
+
+ CLD
+ MOVL p+0(FP), DI
+ MOVBLZX c+4(FP), AX
+ MOVL n+8(FP), BX
+/*
+ * if not enough bytes, just copy
+ */
+ CMPL BX, $9
+ JLS c3
+/*
+ * build word in AX
+ */
+ MOVB AL, AH
+ MOVL AX, CX
+ SHLL $16, CX
+ ORL CX, AX
+/*
+ * copy whole longs
+ */
+c1:
+ MOVL BX, CX
+ SHRL $2, CX
+ ANDL $3, BX
+ REP; STOSL
+/*
+ * copy the rest, by bytes
+ */
+c3:
+ MOVL BX, CX
+ REP; STOSB
+ret:
+ MOVL p+0(FP),AX
+ RET