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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/alpha/lib/strncpy.S
downloadconfigs-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!
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+/*
+ * arch/alpha/lib/strncpy.S
+ * Contributed by Richard Henderson (rth@tamu.edu)
+ *
+ * Copy no more than COUNT bytes of the null-terminated string from
+ * SRC to DST. If SRC does not cover all of COUNT, the balance is
+ * zeroed.
+ *
+ * Or, rather, if the kernel cared about that weird ANSI quirk. This
+ * version has cropped that bit o' nastiness as well as assuming that
+ * __stxncpy is in range of a branch.
+ */
+
+ .set noat
+ .set noreorder
+
+ .text
+
+ .align 4
+ .globl strncpy
+ .ent strncpy
+strncpy:
+ .frame $30, 0, $26
+ .prologue 0
+
+ mov $16, $0 # set return value now
+ beq $18, $zerolen
+ unop
+ bsr $23, __stxncpy # do the work of the copy
+
+ unop
+ bne $18, $multiword # do we have full words left?
+ subq $24, 1, $3 # nope
+ subq $27, 1, $4
+
+ or $3, $24, $3 # clear the bits between the last
+ or $4, $27, $4 # written byte and the last byte in COUNT
+ andnot $4, $3, $4
+ zap $1, $4, $1
+
+ stq_u $1, 0($16)
+ ret
+
+ .align 4
+$multiword:
+ subq $24, 1, $2 # clear the final bits in the prev word
+ or $2, $24, $2
+ zapnot $1, $2, $1
+ subq $18, 1, $18
+
+ stq_u $1, 0($16)
+ addq $16, 8, $16
+ unop
+ beq $18, 1f
+
+ nop
+ unop
+ nop
+ blbc $18, 0f
+
+ stq_u $31, 0($16) # zero one word
+ subq $18, 1, $18
+ addq $16, 8, $16
+ beq $18, 1f
+
+0: stq_u $31, 0($16) # zero two words
+ subq $18, 2, $18
+ stq_u $31, 8($16)
+ addq $16, 16, $16
+ bne $18, 0b
+
+1: ldq_u $1, 0($16) # clear the leading bits in the final word
+ subq $27, 1, $2
+ or $2, $27, $2
+
+ zap $1, $2, $1
+ stq_u $1, 0($16)
+$zerolen:
+ ret
+
+ .end strncpy