mirror of
https://github.com/RetroPortingToolKit/psxrecomp
synced 2026-10-26 02:11:36 -04:00
Matthew Stanley
38 lines
1.4 KiB
C++
38 lines
1.4 KiB
C++
#pragma once
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#include <array>
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#include <cstdint>
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#include <cstring>
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// A scoped PsyQ Mode 2/Form 1 data view, starting after the 12-byte sync.
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// Only MSF, mode and data submode are synthesized; EDC/ECC are not reproduced.
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// Consumers must guard that their guest callback ignores those fields. The
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// title still owns request selection, guest DMA, callback and queue scheduling.
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class PSXResidentMode2Sector {
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std::array<uint8_t, 2340> bytes_{};
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uint32_t cursor_ = 0;
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bool valid_ = false;
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static uint8_t bcd(uint32_t n) { return uint8_t((n / 10 << 4) | n % 10); }
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public:
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bool assign(uint32_t lba, const uint8_t* data, bool last = false) {
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cursor_ = 0; valid_ = false;
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// MSF has two decimal minute digits. Avoid wrapping on invalid LBAs.
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if (!data || lba >= 450000u - 150u) return false;
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bytes_.fill(0);
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const uint32_t msf = lba + 150;
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bytes_[0] = bcd(msf / 4500);
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bytes_[1] = bcd(msf / 75 % 60);
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bytes_[2] = bcd(msf % 75); bytes_[3] = 2;
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bytes_[6] = bytes_[10] = last ? 0x89 : 0x08;
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std::memcpy(bytes_.data() + 12, data, 2048);
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valid_ = true; return true;
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}
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const uint8_t* take_words(uint32_t words) {
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if (!valid_ || !words || words > (bytes_.size() - cursor_) / 4)
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return nullptr;
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const auto* p = bytes_.data() + cursor_;
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cursor_ += words * 4;
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return p;
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}
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uint32_t consumed() const { return cursor_; }
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};
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