o cleanup
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72
tools/bsnes/chip/obc1/obc1.cpp
Executable file
72
tools/bsnes/chip/obc1/obc1.cpp
Executable file
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#include <../base.hpp>
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#include <../cart/cart.hpp>
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#include "obc1.hpp"
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void OBC1::init() {}
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void OBC1::enable() {}
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void OBC1::power() {
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reset();
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}
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void OBC1::reset() {
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for(unsigned i = 0x0000; i <= 0x1fff; i++) ram_write(i, 0xff);
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status.baseptr = (ram_read(0x1ff5) & 1) ? 0x1800 : 0x1c00;
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status.address = (ram_read(0x1ff6) & 0x7f);
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status.shift = (ram_read(0x1ff6) & 3) << 1;
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}
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uint8 OBC1::read(unsigned addr) {
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addr &= 0x1fff;
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if((addr & 0x1ff8) != 0x1ff0) return ram_read(addr);
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switch(addr) { default: //never used, avoids compiler warning
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case 0x1ff0: return ram_read(status.baseptr + (status.address << 2) + 0);
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case 0x1ff1: return ram_read(status.baseptr + (status.address << 2) + 1);
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case 0x1ff2: return ram_read(status.baseptr + (status.address << 2) + 2);
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case 0x1ff3: return ram_read(status.baseptr + (status.address << 2) + 3);
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case 0x1ff4: return ram_read(status.baseptr + (status.address >> 2) + 0x200);
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case 0x1ff5: case 0x1ff6: case 0x1ff7: return ram_read(addr);
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}
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}
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void OBC1::write(unsigned addr, uint8 data) {
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addr &= 0x1fff;
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if((addr & 0x1ff8) != 0x1ff0) return ram_write(addr, data);
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switch(addr) {
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case 0x1ff0: ram_write(status.baseptr + (status.address << 2) + 0, data); break;
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case 0x1ff1: ram_write(status.baseptr + (status.address << 2) + 1, data); break;
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case 0x1ff2: ram_write(status.baseptr + (status.address << 2) + 2, data); break;
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case 0x1ff3: ram_write(status.baseptr + (status.address << 2) + 3, data); break;
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case 0x1ff4: {
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uint8 temp = ram_read(status.baseptr + (status.address >> 2) + 0x200);
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temp = (temp & ~(3 << status.shift)) | ((data & 3) << status.shift);
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ram_write(status.baseptr + (status.address >> 2) + 0x200, temp);
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} break;
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case 0x1ff5: {
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status.baseptr = (data & 1) ? 0x1800 : 0x1c00;
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ram_write(addr, data);
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} break;
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case 0x1ff6: {
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status.address = (data & 0x7f);
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status.shift = (data & 3) << 1;
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ram_write(addr, data);
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} break;
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case 0x1ff7: {
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ram_write(addr, data);
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} break;
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}
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}
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uint8 OBC1::ram_read(unsigned addr) {
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return memory::cartram.read(addr & 0x1fff);
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}
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void OBC1::ram_write(unsigned addr, uint8 data) {
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memory::cartram.write(addr & 0x1fff, data);
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}
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OBC1::OBC1() {}
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OBC1::~OBC1() {}
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