oreodave/avm
Archived
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Fixed bug with converting (h)word to (h)word in terms of endian

Browse Source 
While it helped with understanding to use unions as a safe way to
access the underlying bits, this shift based mechanism actually makes
more sense at a glance, particularly by utilising WORD_NTH_BYTE
This commit is contained in:
Aryadev Chavali
2024-04-28 20:57:41 +05:30
parent 7ca9f1b98b
commit 08c9726333
3 changed files with 10 additions and 71 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
lib/base.c
View File

@@ -14,60 +14,16 @@
#include <string.h>
union hword_pun
hword_t hword_byteswap(const hword_t w)
{
hword_t h;
byte_t bytes[HWORD_SIZE];
};
union word_pun
{
word_t h;
byte_t bytes[WORD_SIZE];
};
hword_t hword_htobc(hword_t w)
{
if (LITTLE_ENDIAN)
return w;
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;
return WORD_NTH_BYTE(w, 3) | (WORD_NTH_BYTE(w, 2) << 8) |
(WORD_NTH_BYTE(w, 1) << 16) | (WORD_NTH_BYTE(w, 0) << 24);
}
hword_t hword_bctoh(hword_t w)
word_t word_byteswap(const word_t w)
{
if (LITTLE_ENDIAN)
return w;
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;
}
word_t word_htobc(word_t w)
{
if (LITTLE_ENDIAN)
return w;
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;
}
word_t word_bctoh(word_t w)
{
if (LITTLE_ENDIAN)
return w;
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;
return ((word_t)(hword_byteswap(WORD_NTH_HWORD(w, 0))) << 32) |
hword_byteswap(WORD_NTH_HWORD(w, 1));
}
hword_t convert_bytes_to_hword(const byte_t *bytes)

21
lib/base.h
View File

@@ -166,25 +166,8 @@ word_t convert_bytes_to_word(const byte_t *);
*/
void convert_word_to_bytes(const word_t w, byte_t *buffer);
/**
@brief Convert a half word into bytecode format (little endian)
*/
hword_t hword_htobc(const hword_t);
hword_t hword_byteswap(const hword_t h);
/**
@brief Convert a half word in bytecode format (little endian) to
host format
*/
hword_t hword_bctoh(const hword_t);
/**
@brief Convert a word into bytecode format (little endian)
*/
word_t word_htobc(const word_t);
/**
@brief Convert a word in bytecode format (little endian) to host format
*/
word_t word_bctoh(const word_t);
word_t word_byteswap(const word_t w);
#endif

4
lib/inst.c
View File

@@ -431,9 +431,9 @@ size_t prog_write_bytecode(prog_t program, byte_t *bytes, size_t size_bytes)
if (size_bytes < PROG_HEADER_SIZE || prog_bytecode_size(program) < size_bytes)
return 0;
// Write program header i.e. the start and count
word_t start = word_htobc(program.start_address);
word_t start = word_byteswap(program.start_address);
*(bytes++) = start;
word_t count = word_htobc(program.count);
word_t count = word_byteswap(program.count);
*(bytes++) = count;
// Write instructions