decodetree: Use Python3 floor division operator

This script started using Python2, where the 'classic' division
operator returns the floor result. In commit 3d004a37 we started
to use Python3, where the division operator returns the float
result ('true division').
To keep the same behavior, use the 'floor division' operator "//"
which returns the floor result.

Fixes: 3d004a37
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200330121345.14665-1-f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

scripts/decodetree.py

@@ -1025,7 +1025,7 @@ def output_code(self, i, extracted, outerbits, outermask):
         if extracted < self.width:
             output(ind, 'insn = ', decode_function,
                    '_load_bytes(ctx, insn, {0}, {1});\n'
-                   .format(extracted / 8, self.width / 8));
+                   .format(extracted // 8, self.width // 8));
             extracted = self.width
 
         # Attempt to aid the compiler in producing compact switch statements.
@@ -1079,7 +1079,7 @@ def output_code(self, i, extracted, outerbits, outermask):
         if extracted < self.width:
             output(ind, 'insn = ', decode_function,
                    '_load_bytes(ctx, insn, {0}, {1});\n'
-                   .format(extracted / 8, self.width / 8));
+                   .format(extracted // 8, self.width // 8));
             extracted = self.width
         output(ind, 'return insn;\n')
 # end SizeLeaf