Index: src/trusted/validator_ragel/decoding.h |
=================================================================== |
--- src/trusted/validator_ragel/decoding.h (revision 9911) |
+++ src/trusted/validator_ragel/decoding.h (working copy) |
@@ -12,7 +12,7 @@ |
#ifndef NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_RAGEL_DECODING_H_ |
#define NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_RAGEL_DECODING_H_ |
-#include "native_client/src/trusted/validator_ragel/unreviewed/decoder.h" |
+#include "native_client/src/trusted/validator_ragel/decoder.h" |
#if NACL_WINDOWS |
# define FORCEINLINE __forceinline |
@@ -84,6 +84,62 @@ |
return is4 >> 4; |
} |
+/* |
+ * SignExtendXXBit is used to sign-extend XX-bit value to unsigned 64-bit value. |
+ * |
+ * To do that you need to pass unsigned value of smaller then 64-bit size |
+ * to this function: it will be converted to signed value and then |
+ * sign-extended to become 64-bit value. |
+ * |
+ * Smaller values can be obtained by restricting this value further (which is |
+ * safe according to the C language specification: see 6.2.1.2 in C90 and |
+ * 6.3.1.3.2 in C99 specification). |
+ * |
+ * Note that these operations are safe but slightly unusual: they come very |
+ * close to the edge of what “well-behaved C program is not supposed to do”, |
+ * but they stay on the “safe” side of this boundary. Specifically: this |
+ * behavior triggers “implementation-defined behavior” (see 6.2.1.2 in C90 |
+ * specification and 6.3.1.3.3 in C99 specification) which sounds suspiciously |
+ * similar to the dreaded “undefined behavior”, but in reality these two are |
+ * quite different: any program which triggers “undefined behavior” is not a |
+ * valid C program at all, but program which tirggers “implementation-defined |
+ * behavior” is quite valid C program. What this program actually *does* |
+ * depends on the specification of a given C compiler: each particular |
+ * implementation must decide for itself what it'll do in this particular case |
+ * and *stick* *to* *it*. If the implementation uses two's-complement negative |
+ * numbers (and all the implementation which can compile this code *must* |
+ * support two's-complement arythmetic—see 7.18.1.1 in C99 specification) then |
+ * the easiest thing to do is to do what we need here—this is what all known |
+ * compilers for all known platforms are actually doing. |
+ */ |
+static FORCEINLINE uint64_t SignExtend8Bit(int8_t value) { |
+ return value; |
+} |
+ |
+static FORCEINLINE uint64_t SignExtend16Bit(int16_t value) { |
+ return value; |
+} |
+ |
+static FORCEINLINE uint64_t SignExtend32Bit(int32_t value) { |
+ return value; |
+} |
+ |
+static FORCEINLINE uint64_t AnyFieldValue8bit(const uint8_t *start) { |
+ return *start; |
+} |
+ |
+static FORCEINLINE uint64_t AnyFieldValue16bit(const uint8_t *start) { |
+ return (start[0] + 256U * start[1]); |
+} |
+ |
+static FORCEINLINE uint64_t AnyFieldValue32bit(const uint8_t *start) { |
+ return (start[0] + 256U * (start[1] + 256U * (start[2] + 256U * (start[3])))); |
+} |
+static FORCEINLINE uint64_t AnyFieldValue64bit(const uint8_t *start) { |
+ return (*start + 256ULL * (start[1] + 256ULL * (start[2] + 256ULL * |
+ (start[3] + 256ULL * (start[4] + 256ULL * (start[5] + 256ULL * |
+ (start[6] + 256ULL * start[7]))))))); |
+} |
static const uint8_t index_registers[] = { |
/* Note how REG_RIZ falls out of the pattern. */ |
REG_RAX, REG_RCX, REG_RDX, REG_RBX, |