mirror of
https://github.com/V2RetroComputing/analog.git
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73 lines
2.2 KiB
C
73 lines
2.2 KiB
C
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#include <string.h>
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#include <hardware/pio.h>
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#include "common/config.h"
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#include "abus.pio.h"
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#include "parallel/businterface.h"
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#include "parallel/parallelbuffer.h"
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volatile uint8_t parallel_tx_reg = 0x00;
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volatile uint8_t parallel_strobe = 0x00;
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static inline void __time_critical_func(parallel_write)(uint32_t address, uint32_t value) {
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uint8_t last_strobe = parallel_strobe;
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if(address & 0x1) {
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parallel_tx_reg = value;
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}
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if(address & 0x2) {
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parallel_strobe = 1;
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}
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if((last_strobe == 0) && (parallel_strobe == 1)) {
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parallel_tx_push(parallel_tx_reg);
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}
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if(address & 0x4) {
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parallel_strobe = 0;
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}
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}
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static inline void __time_critical_func(shadow_memory)(uint32_t address, uint32_t value) {
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// Shadow parts of the Apple's memory by observing the bus write cycles
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if((value & (1u << CONFIG_PIN_APPLEBUS_RW-CONFIG_PIN_APPLEBUS_DATA_BASE)) == 0) {
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if(CARD_SELECT) {
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if(CARD_DEVSEL) {
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parallel_write(address, value);
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} else if(address < 0xC000) {
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apple_memory[address] = value;
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}
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// Config memory in card slot-rom address space
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if(CARD_IOSEL) {
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config_memory[address & 0x1F] = value;
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if((address & 0xFF) == 0xFF)
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config_handler();
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}
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}
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}
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}
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void __time_critical_func(parallel_businterface)() {
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while(v2mode == MODE_PARALLEL) {
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uint32_t value = pio_sm_get_blocking(CONFIG_ABUS_PIO, ABUS_MAIN_SM);
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uint32_t dout;
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uint32_t address = (value >> 10) & 0xffff;
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if((value & (1u << CONFIG_PIN_APPLEBUS_RW-CONFIG_PIN_APPLEBUS_DATA_BASE)) != 0) {
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if(CARD_SELECT) {
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if(CARD_DEVSEL) {
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dout = ((address & 0xf) == 0) ? parallel_status : 0xff;
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} else {
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dout = apple_memory[address];
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}
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// device read access
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pio_sm_put_blocking(CONFIG_ABUS_PIO, ABUS_DEVICE_READ_SM, dout);
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}
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}
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shadow_memory(address, value);
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}
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}
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