From: Chris Hanson <org/chris-hanson/cph>
Date: Sat, 26 Sep 2009 05:22:10 +0000 (-0700)
Subject: Simplify definitions of core object lengths and masks.  Eliminate references to 8... 
X-Git-Tag: 20100708-Gtk~315
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=9aa26658bfc726f0f95dad6c9a07333d4d454fe0;p=mit-scheme.git

Simplify definitions of core object lengths and masks.  Eliminate references to 8-bit types.  Fix a couple of sign errors.
---

diff --git a/src/microcode/object.h b/src/microcode/object.h
index cd403fe89..e86c76a92 100644
--- a/src/microcode/object.h
+++ b/src/microcode/object.h
@@ -38,17 +38,6 @@ USA.
 #  include ";; inconsistency: TYPE_CODE_LENGTH < MIN_TYPE_CODE_LENGTH"
 #endif
 
-#if (TYPE_CODE_LENGTH == 8)
-#  define N_TYPE_CODES (0x100)
-#endif
-#if (TYPE_CODE_LENGTH == 6)
-#  define N_TYPE_CODES (0x40)
-#endif
-#ifndef N_TYPE_CODES
-#  define N_TYPE_CODES (1U << TYPE_CODE_LENGTH)
-#endif
-#define __LOW_TYPE_MASK ((unsigned long) (N_TYPE_CODES - 1U))
-
 typedef unsigned long SCHEME_OBJECT;
 #define SIZEOF_SCHEME_OBJECT SIZEOF_UNSIGNED_LONG
 #define OBJECT_LENGTH ((unsigned int) (CHAR_BIT * SIZEOF_UNSIGNED_LONG))
@@ -56,73 +45,55 @@ typedef unsigned long SCHEME_OBJECT;
 /* A convenience definition since "unsigned char" is so verbose.  */
 typedef unsigned char byte_t;
 
-#if (SIZEOF_UNSIGNED_LONG == 4)	/* 32 bit word versions */
-#  if (TYPE_CODE_LENGTH == 6)
+#if (TYPE_CODE_LENGTH == 6U)
+#  define N_TYPE_CODES (0x40)
+#  if (SIZEOF_UNSIGNED_LONG == 4) /* 32 bit word versions */
 #    define DATUM_LENGTH	(26U)
-#    define FIXNUM_LENGTH	(25U)
+#    define DATUM_MASK		(0x03FFFFFFL)
+#    define TYPE_CODE_MASK	(0XFC000000L)
+#    define FIXNUM_LENGTH	(25U) /* doesn't include sign */
+#    define FIXNUM_MASK		(0x01FFFFFFL)
 #    define FIXNUM_SIGN_BIT	(0x02000000L)
 #    define SIGN_MASK		(0xFE000000L)
 #    define SMALLEST_FIXNUM	(-33554432L)
 #    define BIGGEST_FIXNUM	(33554431L)
 #    define HALF_DATUM_LENGTH	(13U)
 #    define HALF_DATUM_MASK	(0x00001FFFL)
-#    define DATUM_MASK		(0x03FFFFFFL)
-#    define TYPE_CODE_MASK	(0XFC000000L)
-#  endif
-#  if (TYPE_CODE_LENGTH == 8)
-#    define DATUM_LENGTH	(24U)
-#    define FIXNUM_LENGTH	(23U)
-#    define FIXNUM_SIGN_BIT	(0x00800000L)
-#    define SIGN_MASK		(0xFF800000L)
-#    define SMALLEST_FIXNUM	(-8388608)
-#    define BIGGEST_FIXNUM	(8388607)
-#    define HALF_DATUM_LENGTH	(12U)
-#    define HALF_DATUM_MASK	(0x00000FFFL)
-#    define DATUM_MASK		(0x00FFFFFFL)
-#    define TYPE_CODE_MASK	(0xFF000000L)
 #  endif
-#endif
-
-#if (SIZEOF_UNSIGNED_LONG == 8)	/* 64 bit word versions */
-#  if (TYPE_CODE_LENGTH == 6)
+#  if (SIZEOF_UNSIGNED_LONG == 8) /* 64 bit word versions */
 #    define DATUM_LENGTH	(58U)
-#    define FIXNUM_LENGTH	(57U)
+#    define DATUM_MASK		(0x03FFFFFFFFFFFFFFL)
+#    define TYPE_CODE_MASK	(0XFC00000000000000L)
+#    define FIXNUM_LENGTH	(57U) /* doesn't include sign */
+#    define FIXNUM_MASK		(0x01FFFFFFFFFFFFFFL)
 #    define FIXNUM_SIGN_BIT	(0x0200000000000000L)
 #    define SIGN_MASK		(0xFE00000000000000L)
 #    define SMALLEST_FIXNUM	(-144115188075855872L)
 #    define BIGGEST_FIXNUM	(144115188075855871L)
 #    define HALF_DATUM_LENGTH	(29U)
 #    define HALF_DATUM_MASK	(0x000000001FFFFFFFL)
-#    define DATUM_MASK		(0x03FFFFFFFFFFFFFFL)
-#    define TYPE_CODE_MASK	(0XFC00000000000000L)
 #  endif
 #endif
 
 #ifndef DATUM_LENGTH		/* Safe versions */
+#  define N_TYPE_CODES		(1U << TYPE_CODE_LENGTH)
 #  define DATUM_LENGTH		(OBJECT_LENGTH - TYPE_CODE_LENGTH)
-   /* FIXNUM_LENGTH does NOT include the sign bit! */
-#  define FIXNUM_LENGTH		(DATUM_LENGTH - 1U)
+#  define DATUM_MASK		((1UL << DATUM_LENGTH) - 1UL)
+#  define TYPE_CODE_MASK	((N_TYPE_CODES - 1U) << DATUM_LENGTH)
+#  define FIXNUM_LENGTH		(DATUM_LENGTH - 1U) /* doesn't include sign */
+#  define FIXNUM_MASK		((1UL << FIXNUM_LENGTH) - 1UL)
 #  define FIXNUM_SIGN_BIT	(1UL << FIXNUM_LENGTH)
-#  define __SIGN_MASK		((unsigned long) ((N_TYPE_CODES * 2U) - 1U))
-#  define SIGN_MASK		(__SIGN_MASK << FIXNUM_LENGTH)
+#  define SIGN_MASK							\
+  (((unsigned long) ((N_TYPE_CODES * 2U) - 1U)) << FIXNUM_LENGTH)
 #  define SMALLEST_FIXNUM	SIGN_MASK
-#  define BIGGEST_FIXNUM	((1UL << FIXNUM_LENGTH) - 1U)
+#  define BIGGEST_FIXNUM	((1UL << FIXNUM_LENGTH) - 1UL)
 #  define HALF_DATUM_LENGTH	(DATUM_LENGTH / 2U)
 #  define HALF_DATUM_MASK	((1UL << HALF_DATUM_LENGTH) - 1UL)
-#  define DATUM_MASK		((1UL << DATUM_LENGTH) - 1UL)
-#  define TYPE_CODE_MASK	(__LOW_TYPE_MASK << DATUM_LENGTH)
 #endif
 
 /* Basic object structure */
 
-#ifndef OBJECT_TYPE
-#  ifdef UNSIGNED_SHIFT_BUG
-#    define OBJECT_TYPE(object) (((object) >> DATUM_LENGTH) & __LOW_TYPE_MASK)
-#  else
-#    define OBJECT_TYPE(object) ((object) >> DATUM_LENGTH)
-#  endif
-#endif
-
+#define OBJECT_TYPE(object) ((object) >> DATUM_LENGTH)
 #define OBJECT_DATUM(object) ((object) & DATUM_MASK)
 #define OBJECT_ADDRESS(object) (DATUM_TO_ADDRESS (OBJECT_DATUM (object)))