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Implement ds align[alignment, offset] (#1181)

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This commit is contained in:
Rangi
2023-11-21 17:57:47 -05:00
committed by GitHub
parent 6f0ffcf3e1
commit 46e29de66f
17 changed files with 148 additions and 17 deletions
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42
src/asm/section.cpp
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@@ -1,5 +1,6 @@
/* SPDX-License-Identifier: MIT */
#include <algorithm>
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
@@ -471,6 +472,27 @@ uint32_t sect_GetOutputOffset(void)
return curOffset + loadOffset;
}
// Returns how many bytes need outputting for the specified alignment and offset to succeed
uint32_t sect_GetAlignBytes(uint8_t alignment, uint16_t offset)
{
struct Section *sect = sect_GetSymbolSection();
if (!sect)
return 0;
bool isFixed = sect->org != (uint32_t)-1;
// If the section is not aligned, no bytes are needed
// (fixed sections count as being maximally aligned for this purpose)
uint8_t curAlignment = isFixed ? 16 : sect->align;
if (curAlignment == 0)
return 0;
// We need `(pcValue + curOffset + return value) % (1 << alignment) == offset`
uint16_t pcValue = isFixed ? sect->org : sect->alignOfs;
return static_cast<uint16_t>(offset - curOffset - pcValue)
% (1u << std::min(alignment, curAlignment));
}
void sect_AlignPC(uint8_t alignment, uint16_t offset)
{
if (!checksection())
@@ -480,20 +502,16 @@ void sect_AlignPC(uint8_t alignment, uint16_t offset)
uint16_t alignSize = 1 << alignment; // Size of an aligned "block"
if (sect->org != (uint32_t)-1) {
if ((sym_GetPCValue() - offset) % alignSize)
if ((sect->org + curOffset - offset) % alignSize)
error("Section's fixed address fails required alignment (PC = $%04" PRIx32
")\n", sym_GetPCValue());
} else if (sect->align != 0) {
if ((((sect->alignOfs + curOffset) % (1 << sect->align)) - offset) % alignSize) {
error("Section's alignment fails required alignment (offset from section start = $%04"
PRIx32 ")\n", curOffset);
} else if (alignment > sect->align) {
sect->align = alignment;
sect->alignOfs = (offset - curOffset) % alignSize;
}
} else {
")\n", sect->org + curOffset);
} else if (sect->align != 0 && (((sect->alignOfs + curOffset) % (1u << sect->align))
- offset) % alignSize) {
error("Section's alignment fails required alignment (offset from section start = $%04"
PRIx32 ")\n", curOffset);
} else if (alignment > sect->align) {
sect->align = alignment;
// We need `(sect->alignOfs + curOffset) % alignSize == offset
// We need `(sect->alignOfs + curOffset) % alignSize == offset`
sect->alignOfs = (offset - curOffset) % alignSize;
}
}