From 50bb696a6b4d75a097f22274834f67961fa9e440 Mon Sep 17 00:00:00 2001
From: Mattias Andrée <m@maandree.se>
Date: Thu, 11 Dec 2025 18:32:27 +0100
Subject: Add signed integers (arithmetics and some testing not implemented
 yet)
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Signed-off-by: Mattias Andrée <m@maandree.se>
---
 libj2.h | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 57 insertions(+), 7 deletions(-)

(limited to 'libj2.h')

diff --git a/libj2.h b/libj2.h
index 6d45d26..dd7fc35 100644
--- a/libj2.h
+++ b/libj2.h
@@ -32,12 +32,29 @@
 #define LIBJ2_JU_BIT ((unsigned)CHAR_BIT * (unsigned)sizeof(uintmax_t))
 
 /**
- * The number of bits in an `struct libj2_j2u`
+ * The number of bits in a `struct libj2_j2u`
  * 
  * @since  1.0
  */
 #define LIBJ2_J2U_BIT (2U * LIBJ2_JU_BIT)
 
+/**
+ * The number of bits in a `struct libj2_j2i`,
+ * including the sign bit
+ * 
+ * @since  1.1
+ */
+#define LIBJ2_J2I_BIT LIBJ2_J2U_BIT
+
+/**
+ * The number of value bits in a `struct libj2_j2i`,
+ * that is, the number of bits excluding the sign
+ * bit
+ * 
+ * @since  1.1
+ */
+#define LIBJ2_J2I_VBIT (LIBJ2_J2I_BIT - 1U)
+
 
 /**
  * Unsigned double-maximum precision integer
@@ -59,6 +76,37 @@ struct libj2_j2u {
 };
 
 
+/**
+ * Signed double-maximum precision integer,
+ * using two's complement
+ * 
+ * libj2 does not implement bitwise operations,
+ * bit-scanning, or bit-rotation operations
+ * for this type, but a `struct libj2_j2i *`
+ * can safetly be casted to `struct libj2_j2u *`
+ * for such operators as well as the for
+ * unsigned bit shifting operations
+ * 
+ * If `a` is the maximum representable value,
+ * `-a - 1` is the minimum representable value;
+ * there is only one zero value (has no sign)
+ * 
+ * @since  1.1
+ */
+struct libj2_j2i {
+	/**
+	 * Most significant half, of which the most
+	 * significant bit is the sign bit
+	 */
+        uintmax_t high;
+
+	/**
+	 * Least significant half
+	 */
+	uintmax_t low;
+};
+
+
 /**
  * Arithmetic overflow prediction result
  * 
@@ -91,15 +139,17 @@ enum libj2_overflow {
 #include "libj2/signum.h"
 #include "libj2/constructors.h"
 #include "libj2/unsigned-comparsion.h"
+#include "libj2/signed-comparsion.h"
+#include "libj2/mixed-comparsion.h"
 #include "libj2/bitwise-logic.h"
+#include "libj2/sign-shifting.h"
 #include "libj2/bit-shifting.h"
 #include "libj2/bit-scanning.h"
-#include "libj2/sign-shifting.h"
-#include "libj2/addition.h"
-#include "libj2/subtraction.h"
-#include "libj2/multiplication.h"
-#include "libj2/division.h"
-#include "libj2/saturated-math.h"
+#include "libj2/addition.h" /* TODO add signed versions */
+#include "libj2/subtraction.h" /* TODO add signed versions */
+#include "libj2/multiplication.h" /* TODO add signed versions */
+#include "libj2/division.h" /* TODO add signed versions */
+#include "libj2/saturated-math.h" /* TODO add signed versions */
 #include "libj2/strings.h"
 
 
-- 
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