52 lines
1.7 KiB
C
52 lines
1.7 KiB
C
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#include "sgb.h"
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void GB_sgb_write(GB_gameboy_t *gb, uint8_t value)
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{
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if (!GB_is_sgb(gb)) return;
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switch ((value >> 4) & 3 ) {
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case 3:
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gb->sgb_ready_for_pulse = true;
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break;
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case 2: // Zero
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if (!gb->sgb_ready_for_pulse || !gb->sgb_ready_for_write) return;
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if (gb->sgb_command_write_index >= sizeof(gb->sgb_command) * 8) {
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GB_log(gb, "Got SGB command: ");
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for (unsigned i = 0; i < 16; i++) {
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GB_log(gb, "%02x ", gb->sgb_command[i]);
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}
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GB_log(gb, "\n");
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gb->sgb_ready_for_pulse = false;
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gb->sgb_ready_for_write = false;
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}
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else {
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gb->sgb_command_write_index++;
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gb->sgb_ready_for_pulse = false;
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}
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break;
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case 1: // One
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if (!gb->sgb_ready_for_pulse || !gb->sgb_ready_for_write) return;
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if (gb->sgb_command_write_index >= sizeof(gb->sgb_command) * 8) {
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GB_log(gb, "Corrupt SGB command.\n");
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gb->sgb_ready_for_pulse = false;
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gb->sgb_ready_for_write = false;
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}
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else {
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gb->sgb_command[gb->sgb_command_write_index / 8] |= 1 << (gb->sgb_command_write_index & 7);
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gb->sgb_command_write_index++;
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gb->sgb_ready_for_pulse = false;
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}
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break;
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case 0:
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gb->sgb_ready_for_pulse = false;
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gb->sgb_ready_for_write = true;
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gb->sgb_command_write_index = 0;
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memset(gb->sgb_command, 0, sizeof(gb->sgb_command));
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break;
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default:
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break;
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}
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}
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