Fix smd format handling for Genesis/Mega Drive#4747
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…/github.com/franckverrot/EmulationResources/blob/master/consoles/megadrive/genesis_rom.txt - Correct header detection: use 16KB alignment check instead of 1KB (SMD files have 512-byte header with 16KB interleaved blocks) - Add content-based interleaving detection by checking "SEGA" signature positions in interleaved format - Fix deinterleave logic: even bytes from first 8KB, odd bytes from last 8KB - Handle trailing bytes that don't form complete 16KB blocks - Skip processing if ROM is already deinterleaved
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Summary
Fixes SMD handling for Genesis/Mega Drive cores. Previously,
.smdfiles would result in a black screen.Changes
SMD Header Detection
fileLength & 0x3FFF == 0x200) instead of 1KB alignmentDeinterleave Logic
0x80='S',0x2080='E',0x81='G',0x2081='A'Technical Details
The previous implementation used 1KB alignment for header detection, which failed for many SMD files. The correct approach is to check for 16KB alignment with 512-byte offset.
Check if completed: