nibblizing
git-svn-id: https://profuse.googlecode.com/svn/branches/v2@268 aa027e90-d47c-11dd-86d7-074df07e0730
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ksherlock
parent
624af11ca1
commit
5f252e4dac
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@ -4,6 +4,8 @@
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#include <cstring>
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#include <Device/Adaptor.h>
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#include <ProFUSE/Exception.h>
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using namespace Device;
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@ -73,5 +75,392 @@ void DOAdaptor::writeBlock(unsigned block, const void *bp)
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#pragma mark -
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#pragma mark NibbleAdaptor
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uint8_t NibbleAdaptor::decode44(uint8_t x, uint8_t y)
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{
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return ((x << 1) | 0x01) & y;
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}
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std::pair<uint8_t, uint8_t> NibbleAdaptor::encode44(uint8_t val)
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{
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uint8_t x = (val >> 1) | 0xaa;
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uint8_t y = val | 0xaa;
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return std::make_pair(x,y);
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}
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uint8_t NibbleAdaptor::encode62(uint8_t val)
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{
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#undef __METHOD__
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#define __METHOD__ "NibbleAdaptor::encode62"
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static uint8_t table[64] = {
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0x96, 0x97, 0x9a, 0x9b, 0x9d, 0x9e, 0x9f, 0xa6,
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0xa7, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb2, 0xb3,
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0xb4, 0xb5, 0xb6, 0xb7, 0xb9, 0xba, 0xbb, 0xbc,
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0xbd, 0xbe, 0xbf, 0xcb, 0xcd, 0xce, 0xcf, 0xd3,
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0xd6, 0xd7, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde,
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0xdf, 0xe5, 0xe6, 0xe7, 0xe9, 0xea, 0xeb, 0xec,
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0xed, 0xee, 0xef, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6,
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0xf7, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
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};
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if (val > 0x3f)
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throw ProFUSE::Exception(__METHOD__ ": Invalid 6-2 value.");
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return table[val];
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}
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uint8_t NibbleAdaptor::decode62(uint8_t val)
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{
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#undef __METHOD__
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#define __METHOD__ "decode62"
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// auto-generated via perl.
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static uint8_t table[] = {
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-1, -1, -1, -1, -1, -1, 0, 1, -1, -1, 2, 3, -1, 4, 5, 6,
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-1, -1, -1, -1, -1, -1, 7, 8, -1, -1, -1, 9, 10, 11, 12, 13,
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-1, -1, 14, 15, 16, 17, 18, 19, -1, 20, 21, 22, 23, 24, 25, 26,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 27, -1, 28, 29, 30,
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-1, -1, -1, 31, -1, -1, 32, 33, -1, 34, 35, 36, 37, 38, 39, 40,
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-1, -1, -1, -1, -1, 41, 42, 43, -1, 44, 45, 46, 47, 48, 49, 50,
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-1, -1, 51, 52, 53, 54, 55, 56, -1, 57, 58, 59, 60, 61, 62, 63
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};
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if ((val < 0x90) || (table[val - 0x90] == 0xff))
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throw ProFUSE::Exception(__METHOD__ ": Invalid 6-2 encoding.");
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return table[val - 0x90];
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}
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static int FindByte(void *address, uint8_t c, unsigned length, unsigned offset = 0)
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{
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for (unsigned i = offset; i < length; ++i)
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{
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if ( *((uint8_t *)address) == c) return i;
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}
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return -1;
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}
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static void LoadBytes(void *src, unsigned length, unsigned offset, void *dest, unsigned count)
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{
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// load with wrap-around.
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if (offset + count < length)
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{
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std::memcpy(dest, (uint8_t *)src + offset, count);
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return;
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}
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unsigned x = length - offset;
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std::memcpy(dest, (uint8_t *)src + offset, x);
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std::memcpy((uint8_t *)dest + x, src, count - x);
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}
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class CircleBuffer {
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public:
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CircleBuffer(void *address, unsigned length)
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{
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_address = (uint8_t *)address;
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_length = length;
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}
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uint8_t operator[](unsigned i) const
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{
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if (i >= _length) i %= _length;
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return _address[i];
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}
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uint8_t& operator[](unsigned i)
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{
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if (i >= _length) i %= _length;
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return _address[i];
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}
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private:
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uint8_t *_address;
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unsigned _length;
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};
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/*
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* Address Field:
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* prologue volume track sector checksum epilogue
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* D5 AA 96 XX YY XX YY XX YY XX YY DE AA EB
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*/
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/*
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* Data Field:
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* prologue user data checksum epilogue
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* D5 AA AD [6+2 encoded] XX DE AA EB
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*/
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/*
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* 0x00
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*------------------------
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* A7 A6 A5 A4 A3 A2 A1 A0
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* B7 B6 B5 B4 B3 B2 B1 B0
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* C7 C6 C5 C4 C3 C2 C1 C0
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* D7 D6 D5 D4 D3 D2 D1 D0
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* E7 E6 E5 E4 E3 E2 E1 E0
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* F7 F6 F5 F4 F3 F2 F1 F0
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* ...
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*------------------------
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* 0x100
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* ||
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* \/
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* 0x00
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* -----------------------
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* 0 0 A7 A6 A5 A4 A3 A2
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* 0 0 B7 B6 B5 B4 B3 B2
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* 0 0 C7 C6 C5 C4 C3 C2
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* 0 0 D7 D6 D5 D4 D3 D2
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* 0 0 E7 E6 E5 E4 E3 E2
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* 0 0 F7 F6 F5 F4 F3 F2
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* ...
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* 0x100 (256):
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* -----------------------
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* ...
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* 0 0 x x x x F0 F1
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* 0 0 x x x x E0 E1
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* 0 0 x x x x D0 D1
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* 0 0 x x x x C0 C1
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* 0 0 x x x x B0 B1
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* 0 0 x x x x A0 A1
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* -----------------------
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* 0x156 (342)
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*
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*
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*
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*
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*
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*
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*
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*/
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NibbleAdaptor::NibbleAdaptor(void *address, unsigned length)
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{
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#undef __METHOD__
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#define __METHOD__ "NibbleAdaptor::NibbleAdaptor"
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_address = (uint8_t *)address;
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_length = length;
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// build a map of track/sectors.
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unsigned state = 0;
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_index.resize(35 * 16, -1);
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int offset = 0;
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unsigned track = 0;
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unsigned sector = 0;
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unsigned volume = 0;
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unsigned checksum = 0;
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CircleBuffer buffer(_address, _length);
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for (;;)
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{
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offset = FindByte(address, 0xd5, length, offset);
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if (offset < 0) break;
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if (buffer[offset + 1] == 0xaa && buffer[offset + 2] == 0x96)
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{
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state = 1;
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volume = decode44(buffer[offset + 3], buffer[offset + 4]);
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track = decode44(buffer[offset + 5], buffer[offset + 6]);
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sector = decode44(buffer[offset + 7], buffer[offset + 8]);
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checksum = decode44(buffer[offset + 9], buffer[offset + 10]);
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if (volume ^ track ^ sector ^ checksum)
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throw ProFUSE::Exception(__METHOD__ ": Invalid address checksum.");
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if (track > 35 || sector > 16)
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throw ProFUSE::Exception(__METHOD__ ": Invalid track/sector.");
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// epilogue is not always de aa eb
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continue;
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}
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if (buffer[offset + 1] == 0xaa && buffer[offset + 2] == 0xad && state == 1)
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{
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_index[track * 16 + sector] = (offset + 3) % _length;
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state = 0;
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continue;
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}
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// ????
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}
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// possible wraparound.
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if (state == 1)
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{
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offset = FindByte(address, 0xd5, length, 0);
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if (offset >= 0)
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{
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if (buffer[offset + 1] == 0xaa && buffer[offset + 2] == 0xad)
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{
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_index[track * 16 + sector] = (offset + 3) % _length;
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}
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}
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}
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// now check _index for offset = -1, which means the sector/track wasn't found.
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for (std::vector<unsigned>::iterator iter = _index.begin(); iter != _index.end(); ++iter)
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{
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if (*iter == -1)
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throw ProFUSE::Exception(__METHOD__ ": Sector missing.");
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}
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}
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void NibbleAdaptor::readTrackSector(TrackSector ts, void *bp)
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{
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#undef __METHOD__
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#define __METHOD__ "NibbleAdaptor::readTrackSector"
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if (ts.track > 35 || ts.sector > 16)
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throw ProFUSE::Exception(__METHOD__ ": Invalid track/sector.");
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CircleBuffer buffer(_address, _length);
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uint8_t bits[86 * 3];
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uint8_t checksum = 0;
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unsigned offset = _index[ts.track * 16 + ts.sector];
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// first 86 bytes are in the auxbuffer, backwards.
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for (unsigned i = 0; i < 86; ++i)
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{
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uint8_t x = buffer[offset + i];
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x = decode62(x);
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checksum ^= x;
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uint8_t y = checksum;
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for (unsigned j = 0; j < 3; ++i)
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{
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bits[i + j * 86] = ((y & 0x01) << 1) | ((y & 0x02) >> 1);
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y >>= 2;
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}
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}
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for (unsigned i = 0; i < 256; ++i)
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{
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uint8_t x = buffer[offset + 86 + i];
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x = decode62(x);
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checksum ^= x;
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uint8_t y = (checksum << 2) | bits[i];
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((uint8_t *)bp)[i] = y;
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}
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if (checksum != buffer[342])
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throw ProFUSE::Exception(__METHOD__ ": Invalid field checksum.");
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}
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void NibbleAdaptor::writeTrackSector(TrackSector ts, const void *bp)
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{
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#undef __METHOD__
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#define __METHOD__ "NibbleAdaptor::readTrackSector"
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if (ts.track > 35 || ts.sector > 16)
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throw ProFUSE::Exception(__METHOD__ ": Invalid track/sector.");
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uint8_t auxBuffer[86];
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uint8_t checksum = 0;
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// create the aux buffer.
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std::memset(auxBuffer, 0, sizeof(auxBuffer));
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for (unsigned i = 0, j = 86, shift = 0; i < 256; ++i)
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{
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uint8_t x = ((const uint8_t *)bp)[i];
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// grab the bottom 2 bytes and reverse them.
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uint8_t y = ((x & 0x01) << 1) | ((x & 0x02) >> 1);
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auxBuffer[--j] |= (y << shift);
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if (j == 0)
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{
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j = 86;
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shift += 2;
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}
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}
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unsigned offset = _index[ts.track * 16 + ts.sector];
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CircleBuffer buffer(_address, _length);
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// create the checksum while writing to disk..
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// aux buffer
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for (unsigned i = 0; i < 86; ++i)
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{
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uint8_t x = auxBuffer[i];
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buffer[offset + i] = encode62(x ^ checksum);
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checksum = x;
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}
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for (unsigned i = 0; i < 256; ++i)
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{
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uint8_t x = ((const uint8_t *)bp)[i];
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x >>= 2;
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buffer[offset + 86 + i] = encode62(x ^ checksum);
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checksum = x;
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}
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buffer[offset + 342] = checksum;
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}
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@ -1,8 +1,13 @@
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#ifndef __DEVICE_ADAPTOR_H__
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#define __DEVICE_ADAPTOR_H__
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#include <utility>
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#include <vector>
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#include <stdint.h>
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#include <Device/TrackSector.h>
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namespace Device {
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class Adaptor
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@ -38,6 +43,34 @@ namespace Device {
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// TODO -- nibble adaptor.
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class NibbleAdaptor : public Adaptor
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{
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public:
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NibbleAdaptor(void *address, unsigned length);
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virtual ~NibbleAdaptor();
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virtual void readBlock(unsigned block, void *bp);
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virtual void writeBlock(unsigned block, const void *bp);
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virtual void readTrackSector(TrackSector ts, void *bp);
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virtual void writeTrackSector(TrackSector ts, const void *bp);
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static std::pair<uint8_t, uint8_t>encode44(uint8_t);
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static uint8_t decode44(uint8_t, uint8_t);
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static uint8_t encode62(uint8_t);
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static uint8_t decode62(uint8_t);
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private:
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uint8_t *_address;
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unsigned _length;
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std::vector<unsigned> _index;
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};
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}
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