Zack Buhman
d912278afd
The serial_transfer loader, as long as the target program voluntarily terminates itself at some point, is able to load multiple programs consecutively without requiring a physical power cycle to reload the transfer program from CD. The current example.mk juggles between two different "memory layouts", one for "burn to a physical CD" and another for "load via serial cable". Because the serial_transfer program now relocates itself to the end of system memory, this means the 0x8c010000 area is now usable by programs that are loaded by serial_transfer.
149 lines
2.8 KiB
C++
149 lines
2.8 KiB
C++
#include <cstdint>
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#include "sh7091/sh7091.hpp"
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#include "sh7091/sh7091_bits.hpp"
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#include "sh7091/serial.hpp"
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#include "holly/holly.hpp"
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enum load_command {
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CMD_NONE,
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CMD_DATA, // DATA 0000 0000 {data}
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CMD_JUMP, // JUMP 0000
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};
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struct load_state {
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union {
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uint8_t buf[12];
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struct {
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uint8_t cmd[4];
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uint32_t addr1;
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uint32_t addr2;
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};
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};
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uint32_t len;
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enum load_command command;
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};
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static struct load_state state;
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void move(void *dst, const void *src, size_t n)
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{
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uint8_t * d = reinterpret_cast<uint8_t *>(dst);
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const uint8_t * s = reinterpret_cast<const uint8_t *>(src);
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if (d==s) return;
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if (d<s) {
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for (; n; n--) *d++ = *s++;
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} else {
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while (n) n--, d[n] = s[n];
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}
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}
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void load_init()
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{
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state.len = 0;
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state.command = CMD_NONE;
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}
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void debug(const char * s)
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{
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char c;
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while ((c = *s++)) {
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using namespace scif;
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while ((sh7091.SCIF.SCFSR2 & scfsr2::tdfe::bit_mask) == 0);
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sh7091.SCIF.SCFTDR2 = (uint8_t)c;
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}
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}
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void jump_to_func(const uint32_t addr)
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{
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serial::string("jump to: ");
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serial::integer<uint32_t>(addr);
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// save our stack
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asm volatile ("ldc r15, gbr; "
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"mov #0, r15; "
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"jsr @%0; "
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"nop; "
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"stc gbr, r15; "
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:
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: "r"(addr) /* input */
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/* clobbered register */
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: "r0","r1","r2","r3","r4","r5","r6","r7","r8","r9","r10","r11","r12","macl","mach","gbr","pr"
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);
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// restore our stack
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}
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void load_recv(uint8_t c)
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{
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if (state.command == CMD_NONE)
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state.buf[state.len++] = c;
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while (1) {
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switch (state.command) {
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case CMD_NONE:
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if (state.len >= 4) {
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if (state.buf[0] == 'D' &&
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state.buf[1] == 'A' &&
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state.buf[2] == 'T' &&
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state.buf[3] == 'A') {
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if (state.len < 12) {
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return;
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} else {
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debug("data\n");
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state.command = CMD_DATA;
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return;
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}
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} else if (state.buf[0] == 'J' &&
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state.buf[1] == 'U' &&
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state.buf[2] == 'M' &&
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state.buf[3] == 'P') {
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if (state.len < 8) {
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return;
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} else {
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debug("jump\n");
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state.command = CMD_JUMP;
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}
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} else {
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move(&state.buf[0], &state.buf[4], state.len - 4);
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state.len -= 4;
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}
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} else {
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return;
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}
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break;
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case CMD_DATA:
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{
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uint32_t * size = &state.addr1;
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uint8_t * dest = reinterpret_cast<uint8_t *>(state.addr2);
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if (*size > 0) {
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sh7091.SCIF.SCFTDR2 = c;
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// write c to dest
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*dest = c;
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state.addr2++;
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(*size)--;
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}
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if (*size == 0) {
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state.len = 0;
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state.command = CMD_NONE;
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debug("next\n");
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}
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return;
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break;
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}
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case CMD_JUMP:
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// jump
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state.len = 0;
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state.command = CMD_NONE;
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debug("prejump\n");
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holly.VO_BORDER_COL = (31 << 11);
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jump_to_func(state.addr1);
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holly.VO_BORDER_COL = (63 << 5) | (31 << 0);
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debug("postjump\n");
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return;
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break;
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}
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}
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}
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