mirror of
https://github.com/ekeeke/Genesis-Plus-GX.git
synced 2024-12-25 18:51:49 +01:00
420 lines
11 KiB
C
420 lines
11 KiB
C
#include "shared.h"
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#include "rominfo.h"
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#define GAME_COUNT 21
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typedef struct
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{
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char game_id[14];
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uint16 chk;
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T_EEPROM_TYPE type;
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} T_GAME_ENTRY;
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T_GAME_ENTRY database[GAME_COUNT] =
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{
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/* ACCLAIM mappers */
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/* 24C02 (old mapper) */
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{{"T-081326" }, 0, {8, 0xFF, 0xFF, 0x200000, 0x200000, 0x200000, 0, 1, 1}}, /* NBA Jam (UE) */
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{{"T-81033" }, 0, {8, 0xFF, 0xFF, 0x200000, 0x200000, 0x200000, 0, 1, 1}}, /* NBA Jam (J) */
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/* 24C02 */
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{{"T-81406" }, 0, {8, 0xFF, 0xFF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* NBA Jam TE */
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{{"T-081276" }, 0, {8, 0xFF, 0xFF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* NFL Quarterback Club */
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/* 24C16 */
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{{"T-081586" }, 0, {8, 0x7FF, 0x7FF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* NFL Quarterback Club '96 */
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/* 24C65 */
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{{"T-81576" }, 0, {16, 0x1FFF, 0x1FFF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* College Slam */
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{{"T-81476" }, 0, {16, 0x1FFF, 0x1FFF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* Frank Thomas Big Hurt Baseball */
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/* EA mapper (24C01 only) */
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{{"T-50396" }, 0, {7, 0x7F, 0x7F, 0x200000, 0x200000, 0x200000, 7, 7, 6}}, /* NHLPA Hockey 93 (UE) */
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{{"T-50176" }, 0, {7, 0x7F, 0x7F, 0x200000, 0x200000, 0x200000, 7, 7, 6}}, /* Rings of Power */
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/* SEGA mapper (24C01 only) */
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{{"T-12046" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Megaman - The Wily Wars */
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{{"T-12053" }, 0xEA80, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Rockman Mega World (J) [A] */
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{{"MK-1215" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Evander 'Real Deal' Holyfield's Boxing */
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{{"MK-1228" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Greatest Heavyweights of the Ring (U) */
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{{"G-5538" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Greatest Heavyweights of the Ring (J) */
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{{"PR-1993" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Greatest Heavyweights of the Ring (E) */
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{{"G-4060" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Wonderboy in Monster World */
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/* CODEMASTERS mapper */
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/* 24C08 */
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{{"T-120096" }, 0, {8, 0x3FF, 0x3FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Micro Machines 2 - Turbo Tournament (E) */
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{{"00000000-00"}, 0x168B, {8, 0x3FF, 0x3FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Micro Machines Military */
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{{"00000000-00"}, 0xCEE0, {8, 0x3FF, 0x3FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Micro Machines Military (Bad)*/
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/* 24C16 */
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{{"00000000-00"}, 0x165E, {8, 0x7FF, 0x7FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Micro Machines Turbo Tournament 96 */
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{{"00000000-00"}, 0x2C41, {8, 0x7FF, 0x7FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}} /* Micro Machines Turbo Tournament 96 (Bad)*/
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};
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T_EEPROM eeprom;
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void EEPROM_Init()
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{
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uint8 i = 0;
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/* initialize eeprom */
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memset(&eeprom, 0, sizeof(T_EEPROM));
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eeprom.sda = eeprom.old_sda = 1;
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eeprom.scl = eeprom.old_scl = 1;
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eeprom.state = STAND_BY;
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sram.custom = 0;
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/* look into game database */
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while ((i<GAME_COUNT) && (!sram.custom))
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{
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if (strstr(rominfo.product,database[i].game_id) != NULL)
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{
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/* additional check (Micro Machines, Rockman Mega World) */
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if ((database[i].chk == 0) || (database[i].chk == rominfo.checksum))
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{
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sram.custom = 1;
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sram.on = 1;
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sram.write = 1;
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memcpy(&eeprom.type, &database[i].type, sizeof(T_EEPROM_TYPE));
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}
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}
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i++;
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}
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if (sram.custom)
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{
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/* set SRAM start & end address */
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sram.start = sram.end = eeprom.type.sda_in_adr;
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if (sram.end < eeprom.type.sda_out_adr) sram.end = eeprom.type.sda_out_adr;
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if (sram.end < eeprom.type.scl_adr) sram.end = eeprom.type.scl_adr;
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if (sram.start > eeprom.type.sda_out_adr) sram.start = eeprom.type.sda_out_adr;
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if (sram.start > eeprom.type.scl_adr) sram.start = eeprom.type.scl_adr;
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}
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else if ((sram.end - sram.start) < 2)
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{
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/* Game not found in database but header indicates it uses EEPROM */
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sram.custom = 1;
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sram.on = 1;
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sram.write = 1;
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/* set SEGA mapper as default */
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memcpy(&eeprom.type, &database[9].type, sizeof(T_EEPROM_TYPE));
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}
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}
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static void Detect_START()
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{
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if (eeprom.old_scl && eeprom.scl)
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{
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if (eeprom.old_sda && !eeprom.sda)
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{
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eeprom.cycles = 0;
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eeprom.slave_mask = 0;
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if (eeprom.type.address_bits == 7)
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{
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eeprom.word_address = 0;
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eeprom.state = GET_WORD_ADR_7BITS;
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}
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else eeprom.state = GET_SLAVE_ADR;
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}
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}
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}
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static void Detect_STOP()
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{
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if (eeprom.old_scl && eeprom.scl)
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{
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if (!eeprom.old_sda && eeprom.sda)
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{
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eeprom.state = STAND_BY;
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}
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}
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}
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void EEPROM_Write(unsigned int address, unsigned int value)
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{
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uint16 sram_address = 0;
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/* decode SCL and SDA value */
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if (eeprom.type.sda_in_adr == address) eeprom.sda = (value >> eeprom.type.sda_in_bit) & 1;
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else eeprom.sda = eeprom.old_sda;
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if (eeprom.type.scl_adr == address) eeprom.scl = (value >> eeprom.type.scl_bit) & 1;
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else eeprom.scl = eeprom.old_scl;
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/* EEPROM current state */
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switch (eeprom.state)
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{
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/* Standby Mode */
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case STAND_BY:
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Detect_START();
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Detect_STOP();
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break;
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/* Suspended Mode */
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case WAIT_STOP:
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Detect_STOP();
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break;
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/* Get Word Address 7 bits: MODE-1 only (24C01)
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* and R/W bit
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*/
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case GET_WORD_ADR_7BITS:
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Detect_START();
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Detect_STOP();
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/* look for SCL LOW to HIGH transition */
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if (!eeprom.old_scl && eeprom.scl)
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{
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if (eeprom.cycles == 0) eeprom.cycles ++;
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}
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/* look for SCL HIGH to LOW transition */
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if (eeprom.old_scl && !eeprom.scl && (eeprom.cycles > 0))
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{
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if (eeprom.cycles < 8) eeprom.word_address |= (eeprom.old_sda << (7 - eeprom.cycles));
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else if (eeprom.cycles == 8) eeprom.rw = eeprom.old_sda;
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else
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{ /* ACK CYCLE */
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eeprom.cycles = 0;
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eeprom.word_address &= eeprom.type.size_mask;
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eeprom.state = eeprom.rw ? READ_DATA : WRITE_DATA;
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}
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eeprom.cycles ++;
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}
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break;
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/* Get Slave Address (3bits) : MODE-2 & MODE-3 only (24C01 - 24C512) (0-3bits, depending on the array size)
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* or/and Word Address MSB: MODE-2 only (24C04 - 24C16) (0-3bits, depending on the array size)
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* and R/W bit
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*/
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case GET_SLAVE_ADR:
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Detect_START();
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Detect_STOP();
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/* look for SCL LOW to HIGH transition */
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if (!eeprom.old_scl && eeprom.scl)
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{
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if (eeprom.cycles == 0) eeprom.cycles ++;
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}
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/* look for SCL HIGH to LOW transition */
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if (eeprom.old_scl && !eeprom.scl && (eeprom.cycles > 0))
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{
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if ((eeprom.cycles > 4) && (eeprom.cycles <8))
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{
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if ((eeprom.type.address_bits == 16) ||
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(eeprom.type.size_mask < (1 << (15 - eeprom.cycles))))
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{
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/* this is a SLAVE ADDRESS bit */
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eeprom.slave_mask |= (eeprom.old_sda << (7 - eeprom.cycles));
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}
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else
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{
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/* this is a WORD ADDRESS high bit */
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if (eeprom.old_sda) eeprom.word_address |= (1 << (15 - eeprom.cycles));
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else eeprom.word_address &= ~(1 << (15 - eeprom.cycles));
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}
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}
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else if (eeprom.cycles == 8) eeprom.rw = eeprom.old_sda;
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else if (eeprom.cycles > 8)
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{
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/* ACK CYCLE */
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eeprom.cycles = 0;
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if (eeprom.type.address_bits == 16)
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{
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/* two ADDRESS bytes */
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eeprom.state = eeprom.rw ? READ_DATA : GET_WORD_ADR_HIGH;
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eeprom.slave_mask <<= 16;
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}
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else
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{
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/* one ADDRESS byte */
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eeprom.state = eeprom.rw ? READ_DATA : GET_WORD_ADR_LOW;
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eeprom.slave_mask <<= 8;
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}
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}
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eeprom.cycles ++;
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}
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break;
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/* Get Word Address MSB (4-8bits depending on the array size)
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* MODE-3 only (24C32 - 24C512)
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*/
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case GET_WORD_ADR_HIGH:
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Detect_START();
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Detect_STOP();
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/* look for SCL HIGH to LOW transition */
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if (eeprom.old_scl && !eeprom.scl)
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{
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if (eeprom.cycles < 9)
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{
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if ((eeprom.type.size_mask + 1) < (1 << (17 - eeprom.cycles)))
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{
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/* ignored bit: slave mask should be right-shifted by one */
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eeprom.slave_mask >>= 1;
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}
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else
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{
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/* this is a WORD ADDRESS high bit */
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if (eeprom.old_sda) eeprom.word_address |= (1 << (16 - eeprom.cycles));
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else eeprom.word_address &= ~(1 << (16 - eeprom.cycles));
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}
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eeprom.cycles ++;
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}
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else
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{
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/* ACK CYCLE */
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eeprom.cycles = 1;
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eeprom.state = GET_WORD_ADR_LOW;
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}
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}
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break;
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/* Get Word Address LSB: 7bits (24C01) or 8bits (24C02-24C512)
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* MODE-2 and MODE-3 only (24C01 - 24C512)
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*/
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case GET_WORD_ADR_LOW:
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Detect_START();
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Detect_STOP();
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/* look for SCL HIGH to LOW transition */
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if (eeprom.old_scl && !eeprom.scl)
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{
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if (eeprom.cycles < 9)
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{
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if ((eeprom.type.size_mask + 1) < (1 << (9 - eeprom.cycles)))
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{
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/* ignored bit (X24C01): slave mask should be right-shifted by one */
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eeprom.slave_mask >>= 1;
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}
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else
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{
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/* this is a WORD ADDRESS high bit */
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if (eeprom.old_sda) eeprom.word_address |= (1 << (8 - eeprom.cycles));
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else eeprom.word_address &= ~(1 << (8 - eeprom.cycles));
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}
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eeprom.cycles ++;
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}
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else
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{
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/* ACK CYCLE */
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eeprom.cycles = 1;
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eeprom.word_address &= eeprom.type.size_mask;
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eeprom.state = WRITE_DATA;
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}
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}
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break;
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/*
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* Read Cycle
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*/
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case READ_DATA:
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Detect_START();
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Detect_STOP();
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/* look for SCL HIGH to LOW transition */
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if (eeprom.old_scl && !eeprom.scl)
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{
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if (eeprom.cycles < 9) eeprom.cycles ++;
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else
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{
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eeprom.cycles = 1;
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/* ACK not received */
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if (eeprom.old_sda) eeprom.state = WAIT_STOP;
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}
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}
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break;
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/*
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* Write Cycle
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*/
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case WRITE_DATA:
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Detect_START();
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Detect_STOP();
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/* look for SCL HIGH to LOW transition */
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if (eeprom.old_scl && !eeprom.scl)
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{
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if (eeprom.cycles < 9)
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{
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/* Write DATA bits (max 64kBytes) */
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sram_address = (eeprom.slave_mask | eeprom.word_address) & 0xFFFF;
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if (eeprom.old_sda) sram.sram[sram_address] |= (1 << (8 - eeprom.cycles));
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else sram.sram[sram_address] &= ~(1 << (8 - eeprom.cycles));
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if (eeprom.cycles == 8)
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{
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/* WORD ADDRESS is incremented (roll up at maximum pagesize) */
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eeprom.word_address = (eeprom.word_address & (0xFFFF - eeprom.type.pagewrite_mask)) |
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((eeprom.word_address + 1) & eeprom.type.pagewrite_mask);
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}
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eeprom.cycles ++;
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}
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else eeprom.cycles = 1; /* ACK cycle */
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}
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break;
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}
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eeprom.old_scl = eeprom.scl;
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eeprom.old_sda = eeprom.sda;
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}
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unsigned int EEPROM_Read(unsigned int address)
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{
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uint16 sram_address;
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uint8 sda_out = eeprom.sda;
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/* EEPROM state */
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switch (eeprom.state)
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{
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case READ_DATA:
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if (eeprom.cycles < 9)
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{
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/* Return DATA bits (max 64kBytes) */
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sram_address = (eeprom.slave_mask | eeprom.word_address) & 0xFFFF;
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sda_out = (sram.sram[sram_address] >> (8 - eeprom.cycles)) & 1;
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if (eeprom.cycles == 8)
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{
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/* WORD ADDRESS is incremented (roll up at maximum array size) */
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eeprom.word_address ++;
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eeprom.word_address &= eeprom.type.size_mask;
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}
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}
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break;
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case GET_WORD_ADR_7BITS:
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case GET_SLAVE_ADR:
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case GET_WORD_ADR_HIGH:
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case GET_WORD_ADR_LOW:
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case WRITE_DATA:
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if (eeprom.cycles == 9) sda_out = 0;
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break;
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default:
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break;
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}
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if (address == eeprom.type.sda_out_adr) return (sda_out << eeprom.type.sda_out_bit);
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else return 0;
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}
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