153 lines
3.6 KiB
C
153 lines
3.6 KiB
C
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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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* \__> \/ \/ \/ \/ \/
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*
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* www.optixx.org
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*
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*
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* Version: 1.0
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* Created: 07/21/2009 03:32:16 PM
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* Author: david@optixx.org
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*
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* =====================================================================================
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*/
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#include <stdlib.h>
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#include <stdint.h>
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#include <util/delay.h>
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#include "shared_memory.h"
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#include "config.h"
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#include "sram.h"
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#include "debug.h"
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#include "info.h"
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uint8_t irq_addr_lo;
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uint8_t irq_addr_hi;
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uint8_t scratchpad_state;
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uint8_t scratchpad_cmd;
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uint8_t scratchpad_payload;
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void shared_memory_scratchpad_tx_save()
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{
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scratchpad_state = sram_read(SHARED_MEM_TX_LOC_STATE);
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scratchpad_cmd = sram_read(SHARED_MEM_TX_LOC_CMD);
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scratchpad_payload = sram_read(SHARED_MEM_TX_LOC_PAYLOAD);
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}
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void shared_memory_scratchpad_tx_restore()
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{
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sram_write(SHARED_MEM_TX_LOC_STATE, scratchpad_state);
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sram_write(SHARED_MEM_TX_LOC_CMD, scratchpad_cmd);
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sram_write(SHARED_MEM_TX_LOC_PAYLOAD, scratchpad_payload);
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}
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void shared_memory_irq_hook()
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{
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irq_addr_lo = sram_read(SHARED_IRQ_LOC_LO);
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irq_addr_hi = sram_read(SHARED_IRQ_LOC_HI);
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sram_write(SHARED_IRQ_HANDLER_LO, 0);
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sram_write(SHARED_IRQ_HANDLER_HI, 0);
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}
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void shared_memory_irq_restore()
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{
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sram_write(SHARED_IRQ_LOC_LO, irq_addr_lo);
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sram_write(SHARED_IRQ_LOC_HI, irq_addr_hi);
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}
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void shared_memory_write(uint8_t cmd, uint8_t value)
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{
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info("Write shared memory 0x%04x=0x%02x 0x%04x=0x%02x \n",
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SHARED_MEM_TX_LOC_CMD, cmd, SHARED_MEM_TX_LOC_PAYLOAD, value);
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shared_memory_scratchpad_tx_save();
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shared_memory_irq_hook();
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sram_write(SHARED_MEM_TX_LOC_STATE, SHARED_MEM_TX_SNES_ACK);
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sram_write(SHARED_MEM_TX_LOC_CMD, cmd);
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sram_write(SHARED_MEM_TX_LOC_PAYLOAD, value);
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snes_hirom();
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snes_bus_active();
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#if SHARED_MEM_SWITCH_IRQ
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snes_irq_on();
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snes_irq_lo();
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_delay_us(20);
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snes_irq_hi();
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snes_irq_off();
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#else
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_delay_ms(SHARED_MEM_SWITCH_DELAY);
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#endif
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avr_bus_active();
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snes_lorom();
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shared_memory_scratchpad_tx_restore();
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shared_memory_irq_restore();
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}
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void shared_memory_yield()
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{
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snes_hirom();
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snes_wr_disable();
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snes_bus_active();
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_delay_ms(SHARED_MEM_SWITCH_DELAY);
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avr_bus_active();
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snes_lorom();
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snes_wr_disable();
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}
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int shared_memory_read(uint8_t *cmd, uint8_t *len,uint8_t *buffer)
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{
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uint8_t state;
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state = sram_read(SHARED_MEM_RX_LOC_STATE);
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if (state != SHARED_MEM_RX_AVR_ACK){
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return 1;
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}
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*cmd = sram_read(SHARED_MEM_RX_LOC_CMD);
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*len = sram_read(SHARED_MEM_RX_LOC_LEN);
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info("Read shared memory 0x%04x=0x%02x 0x%04x=0x%02x \n",
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SHARED_MEM_RX_LOC_CMD, *cmd, SHARED_MEM_RX_LOC_LEN, *len);
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sram_bulk_read_buffer(SHARED_MEM_RX_LOC_PAYLOAD,buffer, *len);
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sram_write(SHARED_MEM_RX_LOC_STATE, SHARED_MEM_RX_AVR_RTS);
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snes_hirom();
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snes_bus_active();
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#if SHARED_MEM_SWITCH_IRQ
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snes_irq_on();
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snes_irq_lo();
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_delay_us(20);
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snes_irq_hi();
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snes_irq_off();
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#else
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_delay_ms(SHARED_MEM_SWITCH_DELAY);
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#endif
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avr_bus_active();
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snes_lorom();
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return 0;
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}
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