* first dispatch is based on the tc7-code. The second
* dispatch is based on the actual byte code that is extracted
* from the upper bits.
- * x1-1110-100: characters with x as their least significant bit
- * 10-1110-100: various constants ('flags')
- * x1-1111-100: evaluator byte codes ('ilocs')
+ * x1-1110-100: evaluator byte codes ('ilocs')
+ * x1-1111-100: characters with x as their least significant bit
+ * 10-1111-100: various constants ('flags')
*
*
* Summary of type codes on the heap
enum scm_tags
{
- scm_tc8_char = 0xf4,
- scm_tc8_iloc = 0xfc
+ scm_tc8_iloc = 0xf4,
+ scm_tc8_char = 0xfc,
+ scm_tc9_flag = 0x17c
};
#define SCM_ITAG8(X) (SCM_UNPACK (X) & 0xff)
#define SCM_MAKE_ITAG8(X, TAG) SCM_PACK (((X) << 8) + TAG)
#define SCM_ITAG8_DATA(X) (SCM_UNPACK (X) >> 8)
+#define SCM_ITAG9(X) (SCM_UNPACK (X) & 0x1ff)
+#define SCM_MAKE_ITAG9(X, TAG) SCM_PACK (((X) << 9) + TAG)
+#define SCM_ITAG9_DATA(X) (SCM_UNPACK (X) >> 9)
+
\f
-/* Immediate Symbols, Special Symbols, Flags (various constants).
- */
+/* Flags (various constants and special objects). The indices of the flags
+ * must agree with the declarations in print.c: iflagnames. */
-/* SCM_ISYMP tests for ISPCSYM and ISYM */
-#define SCM_ISYMP(n) ((0x187 & SCM_UNPACK (n)) == 4)
+#define SCM_IFLAGP(n) (SCM_ITAG9 (n) == scm_tc9_flag)
+#define SCM_MAKIFLAG(n) SCM_MAKE_ITAG9 ((n), scm_tc9_flag)
+#define SCM_IFLAGNUM(n) (SCM_ITAG9_DATA (n))
+
+#define SCM_BOOL_F SCM_MAKIFLAG (0)
+#define SCM_BOOL_T SCM_MAKIFLAG (1)
+#define SCM_UNDEFINED SCM_MAKIFLAG (2)
+#define SCM_EOF_VAL SCM_MAKIFLAG (3)
+#define SCM_EOL SCM_MAKIFLAG (4)
+#define SCM_UNSPECIFIED SCM_MAKIFLAG (5)
+
+/* When a variable is unbound this is marked by the SCM_UNDEFINED
+ * value. The following is an unbound value which can be handled on
+ * the Scheme level, i.e., it can be stored in and retrieved from a
+ * Scheme variable. This value is only intended to mark an unbound
+ * slot in GOOPS. It is needed now, but we should probably rewrite
+ * the code which handles this value in C so that SCM_UNDEFINED can be
+ * used instead. It is not ideal to let this kind of unique and
+ * strange values loose on the Scheme level. */
+#define SCM_UNBOUND SCM_MAKIFLAG (6)
+
+/* The Elisp nil value. */
+#define SCM_ELISP_NIL SCM_MAKIFLAG (7)
+
+
+#define SCM_UNBNDP(x) (SCM_EQ_P ((x), SCM_UNDEFINED))
+
+
+/* Short instructions ('special symbols'), long instructions ('immediate
+ * symbols'). The indices of the SCM_IM_ symbols must agree with the
+ * declarations in print.c: scm_isymnames. */
-/* SCM_IFLAGP tests for ISPCSYM, ISYM and IFLAG */
-#define SCM_IFLAGP(n) ((0x87 & SCM_UNPACK (n)) == 4)
-#define SCM_ISYMNUM(n) (SCM_UNPACK (n) >> 9)
-#define SCM_ISYMCHARS(n) (scm_isymnames[SCM_ISYMNUM (n)])
#define SCM_MAKSPCSYM(n) SCM_PACK (((n) << 9) + ((n) << 3) + 4L)
#define SCM_MAKISYM(n) SCM_PACK (((n) << 9) + 0x6cL)
-#define SCM_MAKIFLAG(n) SCM_PACK (((n) << 9) + 0x174L)
+/* SCM_ISYMP tests for ISPCSYM and ISYM */
+#define SCM_ISYMP(n) ((0x187 & SCM_UNPACK (n)) == 4)
+#define SCM_ISYMNUM(n) (SCM_UNPACK (n) >> 9)
SCM_API char *scm_isymnames[]; /* defined in print.c */
-
-/* This table must agree with the declarations
- * in print.c: {Names of immediate symbols}.
- *
- * These are used only in eval but their values
- * have to be allocated here.
- */
+#define SCM_ISYMCHARS(n) (scm_isymnames[SCM_ISYMNUM (n)])
/* Evaluator bytecodes (short instructions): These are uniquely identified by
* their tc7 value. This makes it possible for the evaluator to dispatch on
* them in one step. However, the type system allows for at most 13 short
* instructions. Consequently, the most frequent instructions are chosen to
- * be represented as short instructions. */
+ * be represented as short instructions. These constants are used only in
+ * eval but their values have to be allocated here. */
#define SCM_IM_AND SCM_MAKSPCSYM (0)
#define SCM_IM_BEGIN SCM_MAKSPCSYM (1)
#define SCM_IM_QUOTE SCM_MAKSPCSYM (11)
#define SCM_IM_SET_X SCM_MAKSPCSYM (12)
+
/* Evaluator bytecodes (long instructions): All these share a common tc7
- * value. Thus, the evaluator needs to dispatch on them in two steps. */
+ * value. Thus, the evaluator needs to dispatch on them in two steps. These
+ * constants are used only in eval but their values have to be allocated
+ * here. */
/* Evaluator bytecode for (define ...) statements. We make it a long
- * instruction since the executor will see this bytecode only for a very
+ * instruction since the evaluator will see this bytecode only for a very
* limited number of times, namely once for every top-level and internal
* definition: Top-level definitions are only executed once and internal
* definitions are converted to letrec expressions. */
#define SCM_IM_APPLY SCM_MAKISYM (14)
#define SCM_IM_CONT SCM_MAKISYM (15)
-#define SCM_BOOL_F SCM_MAKIFLAG (16)
-#define SCM_BOOL_T SCM_MAKIFLAG (17)
-#define SCM_UNDEFINED SCM_MAKIFLAG (18)
-#define SCM_EOF_VAL SCM_MAKIFLAG (19)
-#define SCM_EOL SCM_MAKIFLAG (20)
-#define SCM_UNSPECIFIED SCM_MAKIFLAG (21)
-#define SCM_IM_DISPATCH SCM_MAKISYM (22)
-#define SCM_IM_SLOT_REF SCM_MAKISYM (23)
-#define SCM_IM_SLOT_SET_X SCM_MAKISYM (24)
+#define SCM_IM_DISPATCH SCM_MAKISYM (16)
+#define SCM_IM_SLOT_REF SCM_MAKISYM (17)
+#define SCM_IM_SLOT_SET_X SCM_MAKISYM (18)
+#define SCM_IM_DELAY SCM_MAKISYM (19)
+#define SCM_IM_FUTURE SCM_MAKISYM (20)
+#define SCM_IM_CALL_WITH_VALUES SCM_MAKISYM (21)
/* Multi-language support */
-#define SCM_IM_NIL_COND SCM_MAKISYM (25)
-#define SCM_IM_BIND SCM_MAKISYM (26)
-
-#define SCM_IM_DELAY SCM_MAKISYM (27)
-#define SCM_IM_FUTURE SCM_MAKISYM (28)
-#define SCM_IM_CALL_WITH_VALUES SCM_MAKISYM (29)
-
-/* When a variable is unbound this is marked by the SCM_UNDEFINED
- * value. The following is an unbound value which can be handled on
- * the Scheme level, i.e., it can be stored in and retrieved from a
- * Scheme variable. This value is only intended to mark an unbound
- * slot in GOOPS. It is needed now, but we should probably rewrite
- * the code which handles this value in C so that SCM_UNDEFINED can be
- * used instead. It is not ideal to let this kind of unique and
- * strange values loose on the Scheme level.
- */
-#define SCM_UNBOUND SCM_MAKIFLAG (30)
-
-#define SCM_UNBNDP(x) (SCM_EQ_P ((x), SCM_UNDEFINED))
-
-/* The Elisp nil value. */
-#define SCM_ELISP_NIL SCM_MAKIFLAG (31)
+#define SCM_IM_NIL_COND SCM_MAKISYM (22)
+#define SCM_IM_BIND SCM_MAKISYM (23)
\f
HCoop / bpt / guile.git / blobdiff