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44 lines
2.2 KiB
Plaintext
44 lines
2.2 KiB
Plaintext
$NetBSD$
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--- gcc/doc/md.texi.orig Tue Dec 15 18:36:44 2009
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+++ gcc/doc/md.texi
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@@ -4503,8 +4503,9 @@ byte by byte in lexicographic order starting at the be
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string. The instruction is not allowed to prefetch more than one byte
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at a time since either string may end in the first byte and reading past
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that may access an invalid page or segment and cause a fault. The
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-effect of the instruction is to store a value in operand 0 whose sign
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-indicates the result of the comparison.
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+comparison terminates early if the fetched bytes are different or if
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+they are equal to zero. The effect of the instruction is to store a
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+value in operand 0 whose sign indicates the result of the comparison.
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@cindex @code{cmpstr@var{m}} instruction pattern
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@item @samp{cmpstr@var{m}}
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@@ -4522,8 +4523,10 @@ The two memory blocks specified are compared byte by b
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order starting at the beginning of each string. The instruction is not allowed
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to prefetch more than one byte at a time since either string may end in the
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first byte and reading past that may access an invalid page or segment and
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-cause a fault. The effect of the instruction is to store a value in operand 0
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-whose sign indicates the result of the comparison.
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+cause a fault. The comparison will terminate when the fetched bytes
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+are different or if they are equal to zero. The effect of the
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+instruction is to store a value in operand 0 whose sign indicates the
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+result of the comparison.
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@cindex @code{cmpmem@var{m}} instruction pattern
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@item @samp{cmpmem@var{m}}
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@@ -4531,9 +4534,10 @@ Block compare instruction, with five operands like the
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of @samp{cmpstr@var{m}}. The two memory blocks specified are compared
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byte by byte in lexicographic order starting at the beginning of each
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block. Unlike @samp{cmpstr@var{m}} the instruction can prefetch
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-any bytes in the two memory blocks. The effect of the instruction is
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-to store a value in operand 0 whose sign indicates the result of the
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-comparison.
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+any bytes in the two memory blocks. Also unlike @samp{cmpstr@var{m}}
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+the comparison will not stop if both bytes are zero. The effect of
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+the instruction is to store a value in operand 0 whose sign indicates
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+the result of the comparison.
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@cindex @code{strlen@var{m}} instruction pattern
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@item @samp{strlen@var{m}}
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