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Consistently do & alignMask, not % alignSize

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Also add more unrelated tests for coverage
This commit is contained in:
Rangi42
2025-09-23 11:53:05 -04:00
parent 96a75500d3
commit ca4b890273
10 changed files with 98 additions and 38 deletions
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38
src/asm/section.cpp
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@@ -218,14 +218,8 @@ static unsigned int
}
} else if (alignment != 0) {
int32_t curOfs = (alignOffset - sect.size) % alignSize;
if (curOfs < 0) {
curOfs += alignSize;
}
// Make sure any fixed address given is compatible
if (sect.org != UINT32_MAX) {
if (uint32_t curOfs = (alignOffset - sect.size) & alignMask; sect.org != UINT32_MAX) {
if ((sect.org - curOfs) & alignMask) {
sectError(
"Section already declared as fixed at incompatible address $%04" PRIx32,
@@ -624,10 +618,10 @@ uint32_t sect_GetAlignBytes(uint8_t alignment, uint16_t offset) {
return 0;
}
// We need `(pcValue + curOffset + return value) % (1 << alignment) == offset`
// We need `(pcValue + curOffset + return value) & minAlignMask == offset`
uint16_t pcValue = isFixed ? sect->org : sect->alignOfs;
return static_cast<uint16_t>(offset - curOffset - pcValue)
% (1u << std::min(alignment, curAlignment));
uint32_t minAlignMask = (1u << std::min(alignment, curAlignment)) - 1;
return static_cast<uint16_t>(offset - curOffset - pcValue) & minAlignMask;
}
void sect_AlignPC(uint8_t alignment, uint16_t offset) {
@@ -637,13 +631,15 @@ void sect_AlignPC(uint8_t alignment, uint16_t offset) {
assume(alignment <= 16); // Should be ensured by the caller
uint32_t alignSize = 1u << alignment;
uint32_t alignMask = alignSize - 1;
Section *sect = sect_GetSymbolSection();
assume(sect->align <= 16); // Left-shifting by 32 or more would be UB
uint32_t sectAlignSize = 1u << sect->align;
uint32_t sectAlignMask = sectAlignSize - 1;
if (sect->org != UINT32_MAX) {
if (uint32_t actualOffset = (sect->org + curOffset) % alignSize; actualOffset != offset) {
if (uint32_t actualOffset = (sect->org + curOffset) & alignMask; actualOffset != offset) {
error(
"Section is misaligned (at PC = $%04" PRIx32 ", expected ALIGN[%" PRIu32
", %" PRIu32 "], got ALIGN[%" PRIu32 ", %" PRIu32 "])",
@@ -654,8 +650,8 @@ void sect_AlignPC(uint8_t alignment, uint16_t offset) {
actualOffset
);
}
} else if (uint32_t actualOffset = (sect->alignOfs + curOffset) % alignSize;
sect->align != 0 && actualOffset % sectAlignSize != offset % sectAlignSize) {
} else if (uint32_t actualOffset = (sect->alignOfs + curOffset) & alignMask;
sect->align != 0 && (actualOffset & sectAlignMask) != (offset & sectAlignMask)) {
error(
"Section is misaligned ($%04" PRIx32 " bytes into the section, expected ALIGN[%" PRIu32
", %" PRIu32 "], got ALIGN[%" PRIu32 ", %" PRIu32 "])",
@@ -672,8 +668,8 @@ void sect_AlignPC(uint8_t alignment, uint16_t offset) {
sect->org = offset - curOffset;
} else if (alignment > sect->align) {
sect->align = alignment;
// We need `(sect->alignOfs + curOffset) % alignSize == offset`
sect->alignOfs = (offset - curOffset) % alignSize;
// We need `(sect->alignOfs + curOffset) & alignMask == offset`
sect->alignOfs = (offset - curOffset) & alignMask;
}
}
@@ -948,12 +944,11 @@ bool sect_BinaryFile(std::string const &name, uint32_t startPos) {
// The file is seekable; skip to the specified start position
fseek(file, startPos, SEEK_SET);
} else {
// LCOV_EXCL_START
if (errno != ESPIPE) {
// LCOV_EXCL_START
error(
"Error determining size of `INCBIN` file \"%s\": %s", name.c_str(), strerror(errno)
);
// LCOV_EXCL_STOP
}
// The file isn't seekable, so we'll just skip bytes one at a time
while (startPos--) {
@@ -964,6 +959,7 @@ bool sect_BinaryFile(std::string const &name, uint32_t startPos) {
return false;
}
}
// LCOV_EXCL_STOP
}
for (int byte; (byte = fgetc(file)) != EOF;) {
@@ -1013,12 +1009,11 @@ bool sect_BinaryFileSlice(std::string const &name, uint32_t startPos, uint32_t l
// The file is seekable; skip to the specified start position
fseek(file, startPos, SEEK_SET);
} else {
// LCOV_EXCL_START
if (errno != ESPIPE) {
// LCOV_EXCL_START
error(
"Error determining size of `INCBIN` file \"%s\": %s", name.c_str(), strerror(errno)
);
// LCOV_EXCL_STOP
}
// The file isn't seekable, so we'll just skip bytes one at a time
while (startPos--) {
@@ -1029,21 +1024,22 @@ bool sect_BinaryFileSlice(std::string const &name, uint32_t startPos, uint32_t l
return false;
}
}
// LCOV_EXCL_STOP
}
while (length--) {
if (int byte = fgetc(file); byte != EOF) {
writeByte(byte);
} else if (ferror(file)) {
// LCOV_EXCL_START
} else if (ferror(file)) {
error("Error reading `INCBIN` file \"%s\": %s", name.c_str(), strerror(errno));
// LCOV_EXCL_STOP
} else {
error(
"Premature end of `INCBIN` file \"%s\" (%" PRId32 " bytes left to read)",
name.c_str(),
length + 1
);
// LCOV_EXCL_STOP
}
}
return false;