From 2eee382a62a909d5a3f2f5eda94f30fe68fd5335 Mon Sep 17 00:00:00 2001
From: "kr.angelov" <kr.angelov@gmail.com>
Date: Fri, 20 Jan 2012 13:41:10 +0000
Subject: initial import of the C runtime

---
 src/runtime/c/gu/bits.h | 151 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 src/runtime/c/gu/bits.h

(limited to 'src/runtime/c/gu/bits.h')

diff --git a/src/runtime/c/gu/bits.h b/src/runtime/c/gu/bits.h
new file mode 100644
index 000000000..9ba1b0c8e
--- /dev/null
+++ b/src/runtime/c/gu/bits.h
@@ -0,0 +1,151 @@
+#ifndef GU_BITS_H_
+#define GU_BITS_H_
+
+#include <gu/defs.h>
+#include <gu/assert.h>
+
+
+#define GU_WORD_BITS (sizeof(GuWord) * CHAR_BIT)
+
+
+/*
+ * Based on the Bit Twiddling Hacks collection by Sean Eron Anderson
+ * <http://graphics.stanford.edu/~seander/bithacks.html>
+ */
+
+unsigned gu_ceil2e(unsigned i);
+
+static inline int
+gu_sign(int i) {
+	return (i > 0) - (i < 0);
+}
+
+static inline size_t
+gu_ceildiv(size_t size, size_t div)
+{
+	return (size + div - 1) / div;
+}
+
+static inline bool
+gu_aligned(uintptr_t addr, size_t alignment)
+{
+	gu_require(alignment == gu_ceil2e(alignment));
+	return (addr & (alignment - 1)) == 0;
+}
+
+static inline uintptr_t
+gu_align_forward(uintptr_t addr, size_t alignment) {
+	gu_require(alignment == gu_ceil2e(alignment));
+	uintptr_t mask = alignment - 1;
+	return (addr + mask) & ~mask;
+}
+
+static inline uintptr_t
+gu_align_backward(uintptr_t addr, size_t alignment) {
+	gu_require(alignment == gu_ceil2e(alignment));
+	return addr & ~(alignment - 1);
+}
+
+static inline bool
+gu_bits_test(const GuWord* bitmap, int idx) {
+	return !!(bitmap[idx / GU_WORD_BITS] & 1 << (idx % GU_WORD_BITS));
+}
+
+static inline void
+gu_bits_set(GuWord* bitmap, int idx) {
+	bitmap[idx / GU_WORD_BITS] |= ((GuWord) 1) << (idx % GU_WORD_BITS);
+}
+
+static inline void
+gu_bits_clear(GuWord* bitmap, int idx) {
+	bitmap[idx / GU_WORD_BITS] &= ~(((GuWord) 1) << (idx % GU_WORD_BITS));
+}
+
+static inline size_t
+gu_bits_size(size_t n_bits) {
+	return gu_ceildiv(n_bits, GU_WORD_BITS) * sizeof(GuWord);
+}
+
+static inline void*
+gu_word_ptr(GuWord w)
+{
+	return (void*) w;
+}
+
+static inline GuWord
+gu_ptr_word(void* p)
+{
+	return (GuWord) p;
+}
+
+#define GuOpaque() struct { GuWord w_; }
+
+typedef GuWord GuTagged;
+
+#define GU_TAG_MAX (sizeof(GuWord) - 1)
+
+static inline size_t
+gu_tagged_tag(GuTagged t) {
+	return (int) (t & (sizeof(GuWord) - 1));
+}
+
+static inline void*
+gu_tagged_ptr(GuTagged w) {
+	return (void*) gu_align_backward(w, sizeof(GuWord));
+}
+
+static inline GuTagged
+gu_tagged(void* ptr, size_t tag) {
+	gu_require(tag < sizeof(GuWord));
+	uintptr_t u = (uintptr_t) ptr;
+	gu_require(gu_align_backward(u, sizeof(GuWord)) == u);
+	return (GuWord) { u | tag };
+}
+
+#include <gu/exn.h>
+#include <gu/type.h>
+
+extern GU_DECLARE_TYPE(GuIntDecodeExn, abstract);
+
+#define GU_DECODE_2C_(u_, t_, umax_, posmax_, tmin_, err_)	\
+	(((u_) <= (posmax_))					\
+	 ? (t_) (u_)						\
+	 : (tmin_) + ((t_) ((umax_) - (u_))) < 0		\
+	 ? -1 - ((t_) ((umax_) - (u_)))				\
+	 : (gu_raise(err_, GuIntDecodeExn), -1))
+
+
+static inline int8_t
+gu_decode_2c8(uint8_t u, GuExn* err)
+{
+	return GU_DECODE_2C_(u, int8_t, UINT8_C(0xff), 
+			     INT8_C(0x7f), INT8_MIN, err);
+}
+
+static inline int16_t
+gu_decode_2c16(uint16_t u, GuExn* err)
+{
+	return GU_DECODE_2C_(u, int16_t, UINT16_C(0xffff), 
+			     INT16_C(0x7fff), INT16_MIN, err);
+}
+
+static inline int32_t
+gu_decode_2c32(uint32_t u, GuExn* err)
+{
+	return GU_DECODE_2C_(u, int32_t, UINT32_C(0xffffffff), 
+			     INT32_C(0x7fffffff), INT32_MIN, err);
+}
+
+static inline int64_t
+gu_decode_2c64(uint64_t u, GuExn* err)
+{
+	return GU_DECODE_2C_(u, int64_t, UINT64_C(0xffffffffffffffff), 
+			     INT64_C(0x7fffffffffffffff), INT64_MIN, err);
+}
+
+double
+gu_decode_double(uint64_t u);
+
+
+
+#endif // GU_BITS_H_
-- 
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