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authorAryadev Chavali <aryadev@aryadevchavali.com>2024-04-14 03:54:54 +0630
committerAryadev Chavali <aryadev@aryadevchavali.com>2024-04-14 03:54:54 +0630
commit3b912495dec2868f1afae0319471d5ea9451c371 (patch)
tree65d31c9d2b99f2409e90a54dbdd69c588c96a79b /lib/base.c
parente12f36466934dcbc48c0d5847591365191504270 (diff)
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Created custom functions to convert (h)words to and from bytecode format
Instead of using endian.h that is not portable AND doesn't work with C++, I'll just write my own using a forced union based type punning trick. I've decided to use little endian for the format as well: it seems to be used by most desktop computers so it should make these functions faster to run for most CPUs.
Diffstat (limited to 'lib/base.c')
-rw-r--r--lib/base.c72
1 files changed, 68 insertions, 4 deletions
diff --git a/lib/base.c b/lib/base.c
index a2763c4..caa76ae 100644
--- a/lib/base.c
+++ b/lib/base.c
@@ -14,23 +14,87 @@
#include <string.h>
+union hword_pun
+{
+ hword h;
+ byte bytes[HWORD_SIZE];
+};
+
+union word_pun
+{
+ word h;
+ byte bytes[WORD_SIZE];
+};
+
+hword hword_htobc(hword w)
+{
+#if __LITTLE_ENDIAN__
+ return w;
+#else
+ union hword_pun x = {w};
+ union hword_pun y = {0};
+ for (size_t i = 0, j = HWORD_SIZE; i < HWORD_SIZE; ++i, --j)
+ y.bytes[j - 1] = x.bytes[i];
+ return y.h;
+#endif
+}
+
+hword hword_bctoh(hword w)
+{
+#if __LITTLE_ENDIAN__
+ return w;
+#else
+ union hword_pun x = {w};
+ union hword_pun y = {0};
+ for (size_t i = 0, j = HWORD_SIZE; i < HWORD_SIZE; ++i, --j)
+ y.bytes[j - 1] = x.bytes[i];
+ return y.h;
+#endif
+}
+
+word word_htobc(word w)
+{
+#if __LITTLE_ENDIAN__
+ return w;
+#else
+ union word_pun x = {w};
+ union word_pun y = {0};
+ for (size_t i = 0, j = WORD_SIZE; i < WORD_SIZE; ++i, --j)
+ y.bytes[j - 1] = x.bytes[i];
+ return y.h;
+#endif
+}
+
+word word_bctoh(word w)
+{
+#if __LITTLE_ENDIAN__
+ return w;
+#else
+ union word_pun x = {w};
+ union word_pun y = {0};
+ for (size_t i = 0, j = WORD_SIZE; i < WORD_SIZE; ++i, --j)
+ y.bytes[j - 1] = x.bytes[i];
+ return y.h;
+#endif
+}
+
hword convert_bytes_to_hword(byte *bytes)
{
hword be_h = 0;
memcpy(&be_h, bytes, HWORD_SIZE);
- hword h = be32toh(be_h);
+ hword h = hword_bctoh(be_h);
return h;
}
void convert_hword_to_bytes(hword w, byte *bytes)
{
- hword be_h = htobe32(w);
+ hword be_h = hword_htobc(w);
memcpy(bytes, &be_h, HWORD_SIZE);
}
void convert_word_to_bytes(word w, byte *bytes)
{
- word be_w = htobe64(w);
+ word be_w = word_htobc(w);
memcpy(bytes, &be_w, WORD_SIZE);
}
@@ -38,6 +102,6 @@ word convert_bytes_to_word(byte *bytes)
{
word be_w = 0;
memcpy(&be_w, bytes, WORD_SIZE);
- word w = be64toh(be_w);
+ word w = word_bctoh(be_w);
return w;
}