Paul Mathieu
3db383d461
And a few other nice things. The bootloader now has an embedded wozmon! If you know its offset, you can jump to it from the app.
133 lines
2.7 KiB
C++
133 lines
2.7 KiB
C++
#include <cstdint>
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uint8_t UartRead();
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void UartWrite(uint8_t);
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namespace {
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void Jump(uint32_t addr) {
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auto jump = reinterpret_cast<void (*)()>(addr);
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jump();
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}
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constexpr uint8_t kBackspace = 0x7f;
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constexpr uint8_t kOtherBackspace = 0x08;
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uint8_t ReadHexNibble(uint8_t c) {
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// lowercase only
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if (c <= '9') {
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return c - '0';
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}
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return 10 + (c - 'a');
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}
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uint32_t ReadHex(const char* buf) {
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uint32_t out = 0;
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while (*buf == ' ') {
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buf++;
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}
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for (int i = 0; i < 8; i++) {
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uint8_t c = ReadHexNibble(*buf);
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if (c > 0xf) {
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break;
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}
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out = (out << 4) + c;
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buf++;
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}
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return out;
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}
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void WriteHexNibble(uint8_t c) {
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if (c > 9) {
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UartWrite('a' + c - 10);
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} else {
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UartWrite('0' + c);
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}
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}
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void UartWriteUint32(uint32_t a) {
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for (int i = 0; i < 8; i++) {
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WriteHexNibble((a >> 28) & 0xf);
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a <<= 4;
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}
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}
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void UartWriteUint8(uint8_t a) {
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WriteHexNibble(a >> 4);
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WriteHexNibble(a & 0xf);
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}
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void UartDump(uint32_t addr, int count) {
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for (int i = 0; i < count; i++) {
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UartWrite(' ');
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UartWriteUint8(*reinterpret_cast<uint8_t*>(addr + i));
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}
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}
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void DumpHex(uint32_t addr) {
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addr &= 0xfffffffc;
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UartWriteUint32(addr);
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UartWrite(':');
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UartDump(addr, 4);
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UartWrite('\r');
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UartWrite('\n');
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}
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int FindChar(const char* buf, uint8_t c) {
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int found = 0;
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while (*buf) {
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if (*buf == c) {
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return found;
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}
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found++;
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buf++;
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}
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return -1;
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}
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} // namespace
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__attribute__((used))
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void wozmon() {
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uint32_t cur_addr = 0;
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uint32_t cur_data = 0;
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char inbuf[64] = {};
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char* inptr = inbuf;
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while (1) {
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uint8_t c = UartRead();
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UartWrite(c); // echo
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if (c == '\r') {
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*inptr = 0;
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if (inptr == inbuf) {
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cur_addr += 4;
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} else if (FindChar(inbuf, 'r') >= 0) {
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Jump(cur_addr);
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} else {
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cur_addr = ReadHex(inbuf);
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UartWrite('\n');
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}
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DumpHex(cur_addr);
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int assigned = FindChar(inbuf, ':');
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if (assigned >= 0) {
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cur_data = ReadHex(inbuf + assigned + 1);
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*(reinterpret_cast<uint32_t*>(cur_addr)) = cur_data;
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}
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inptr = inbuf;
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} else if (c == kBackspace) {
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inptr--;
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if (inptr < inbuf) {
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inptr = inbuf;
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continue;
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}
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UartWrite(kOtherBackspace);
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UartWrite(' ');
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UartWrite(kOtherBackspace);
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} else {
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*inptr++ = c;
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}
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}
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}
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