arch, x86: add support for arrays as memory operands

Although the cache models support wider accesses, the ISA descriptions
assume that (for the most part) memory operands are integer types,
which makes it difficult to define instructions that do memory accesses
larger than 64 bits.

This patch adds some generic support for memory operands that are arrays
of uint64_t, and specifically a 'u2qw' operand type for x86 that is an
array of 2 uint64_ts (128 bits).  This support is unused at this point,
but will be needed shortly for cmpxchg16b.  Ideally the 128-bit SSE
memory accesses will also be rewritten to use this support.

Support for 128-bit accesses could also have been added using the gcc
__int128_t extension, which would have been less disruptive.  However,
although clang also supports __int128_t, it's still non-standard.
Also, more importantly, this approach creates a path to defining
256- and 512-byte operands as well, which will be useful for eventual
AVX support.

1 files changed, 8 insertions, 3 deletions

diff --git a/src/arch/isa_parser.py b/src/arch/isa_parser.py
index cbc8651d1..749eaf88d 100755
--- a/src/arch/isa_parser.py
+++ b/src/arch/isa_parser.py
@@ -1053,9 +1053,14 @@ stringRE = re.compile(r'"([^"\\]|\\.)*"')
 commentRE = re.compile(r'(^)?[^\S\n]*/(?:\*(.*?)\*/[^\S\n]*|/[^\n]*)($)?',
         re.DOTALL | re.MULTILINE)
 
-# Regular expression object to match assignment statements
-# (used in findOperands())
-assignRE = re.compile(r'\s*=(?!=)', re.MULTILINE)
+# Regular expression object to match assignment statements (used in
+# findOperands()).  If the code immediately following the first
+# appearance of the operand matches this regex, then the operand
+# appears to be on the LHS of an assignment, and is thus a
+# destination.  basically we're looking for an '=' that's not '=='.
+# The heinous tangle before that handles the case where the operand
+# has an array subscript.
+assignRE = re.compile(r'(\[[^\]]+\])?\s*=(?!=)', re.MULTILINE)
 
 def makeFlagConstructor(flag_list):
     if len(flag_list) == 0: