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[/] [eco32/] [tags/] [eco32-0.22/] [stdalone/] [twotasks-1/] [os/] [main.c] - Rev 168
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/* * main.c -- start the ball rolling */ #include "stdarg.h" #include "start.h" /**************************************************************/ int currentTask; unsigned int *currentStkTop; /**************************************************************/ unsigned int task0Stack[256]; unsigned int *task0StkTop = task0Stack + 256; unsigned char task1Code[] = { #include "task1.dump" }; unsigned int task1Stack[256]; unsigned int *task1StkTop = task1Stack + 256; unsigned char task2Code[] = { #include "task2.dump" }; unsigned int task2Stack[256]; unsigned int *task2StkTop = task2Stack + 256; /**************************************************************/ void putchar(char c) { unsigned int *base; if (c == '\n') { putchar('\r'); } base = (unsigned int *) 0xF0300000; while ((*(base + 2) & 1) == 0) ; *(base + 3) = c; } void puts(char *s) { char c; while ((c = *s++) != '\0') { putchar(c); } } void printn(int n) { int a; if (n < 0) { putchar('-'); n = -n; } a = n / 10; if (a != 0) { printn(a); } putchar(n % 10 + '0'); } void printu(unsigned int n, unsigned int b) { unsigned int a; a = n / b; if (a != 0) { printu(a, b); } putchar("0123456789ABCDEF"[n % b]); } void printf(char *fmt, ...) { va_list ap; char c; int n; unsigned int u; char *s; va_start(ap, fmt); while (1) { while ((c = *fmt++) != '%') { if (c == '\0') { va_end(ap); return; } putchar(c); } c = *fmt++; if (c == 'd') { n = va_arg(ap, int); printn(n); } else if (c == 'u' || c == 'o' || c == 'x') { u = va_arg(ap, int); printu(u, c == 'o' ? 8 : (c == 'x' ? 16 : 10)); } else if (c == 's') { s = va_arg(ap, char *); puts(s); } else { putchar(c); } } } /**************************************************************/ static char *exceptionCause[32] = { /* 00 */ "terminal 0 transmitter interrupt", /* 01 */ "terminal 0 receiver interrupt", /* 02 */ "terminal 1 transmitter interrupt", /* 03 */ "terminal 1 receiver interrupt", /* 04 */ "keyboard interrupt", /* 05 */ "unknown interrupt", /* 06 */ "unknown interrupt", /* 07 */ "unknown interrupt", /* 08 */ "disk interrupt", /* 09 */ "unknown interrupt", /* 10 */ "unknown interrupt", /* 11 */ "unknown interrupt", /* 12 */ "unknown interrupt", /* 13 */ "unknown interrupt", /* 14 */ "timer interrupt", /* 15 */ "unknown interrupt", /* 16 */ "bus timeout exception", /* 17 */ "illegal instruction exception", /* 18 */ "privileged instruction exception", /* 19 */ "divide instruction exception", /* 20 */ "trap instruction exception", /* 21 */ "TLB miss exception", /* 22 */ "TLB write exception", /* 23 */ "TLB invalid exception", /* 24 */ "illegal address exception", /* 25 */ "privileged address exception", /* 26 */ "unknown exception", /* 27 */ "unknown exception", /* 28 */ "unknown exception", /* 29 */ "unknown exception", /* 30 */ "unknown exception", /* 31 */ "unknown exception" }; void defaultISR(int irq, unsigned int *registers) { printf("\n%s\n", exceptionCause[irq]); } void initInterrupts(void) { int i; for (i = 0; i < 32; i++) { setISR(i, defaultISR); } } /**************************************************************/ unsigned int getNumber(unsigned char *p) { return (unsigned int) *(p + 0) << 24 | (unsigned int) *(p + 1) << 16 | (unsigned int) *(p + 2) << 8 | (unsigned int) *(p + 3) << 0; } void loadTask(unsigned char *code, unsigned int physCodeAddr, unsigned int physDataAddr) { unsigned int magic; unsigned int csize; unsigned int dsize; unsigned int bsize; unsigned char *virtLoadAddr; int i; magic = getNumber(code); code += sizeof(unsigned int); csize = getNumber(code); code += sizeof(unsigned int); dsize = getNumber(code); code += sizeof(unsigned int); bsize = getNumber(code); code += sizeof(unsigned int); if (magic != 0x1AA09232) { printf("Error: Load module is not executable!\n"); while (1) ; } code += 4 * sizeof(unsigned int); printf("(csize = 0x%x, dsize = 0x%x, bsize = 0x%x)\n", csize, dsize, bsize); virtLoadAddr = (unsigned char *) (0xC0000000 | physCodeAddr); for (i = 0; i < csize; i++) { *virtLoadAddr++ = *code++; } virtLoadAddr = (unsigned char *) (0xC0000000 | physDataAddr); for (i = 0; i < dsize; i++) { *virtLoadAddr++ = *code++; } for (i = 0; i < bsize; i++) { *virtLoadAddr++ = '\0'; } } /**************************************************************/ void trapISR(int irq, unsigned int *registers) { /* 'putchar' is the only system call yet */ putchar(registers[4]); /* skip the trap instruction */ registers[30] += 4; } /**************************************************************/ void missISR(int irq, unsigned int *registers) { if (currentTask == 1) { setTLB(5, 0x00000000, 64 << 12 | 0x01); /* code at 256 k */ setTLB(27, 0x00001000, 68 << 12 | 0x03); /* data at 272 k */ setTLB(22, 0x7FFFF000, 80 << 12 | 0x03); /* user-mode stack at 320 k */ } else if (currentTask == 2) { setTLB(5, 0x00000000, 96 << 12 | 0x01); /* code at 384 k */ setTLB(27, 0x00001000, 100 << 12 | 0x03); /* data at 400 k */ setTLB(22, 0x7FFFF000, 112 << 12 | 0x03); /* user-mode stack at 448 k */ } } void flushTLB(void) { unsigned int invalPage; int i; invalPage = 0xC0000000; for (i = 0; i < 32; i++) { setTLB(i, invalPage, 0); invalPage += (1 << 12); } } /**************************************************************/ void initTimer(void) { unsigned int *timerBase; timerBase = (unsigned int *) 0xF0000000; *(timerBase + 1) = 1000; *timerBase = 2; orMask(1 << 14); } int task1Started = 0; int task2Started = 0; void timerISR(int irq, unsigned int *registers) { unsigned int *timerBase; timerBase = (unsigned int *) 0xF0000000; *timerBase = 2; printf(">|<"); if (currentTask == 0) { if (!task1Started) { /* load & start task1 */ printf("\nOS: loading task1\n"); loadTask(task1Code, 64 << 12, 68 << 12); printf("OS: starting task1\n"); task1Started = 1; currentTask = 1; currentStkTop = task1StkTop; flushTLB(); startTask(); } } else if (currentTask == 1) { if (!task2Started) { /* load & start task2 */ printf("\nOS: loading task2\n"); loadTask(task2Code, 96 << 12, 100 << 12); printf("OS: starting task2\n"); task2Started = 1; currentTask = 2; currentStkTop = task2StkTop; flushTLB(); startTask(); } else { /* switch tasks */ currentTask = 2; currentStkTop = task2StkTop; flushTLB(); } } else if (currentTask == 2) { /* switch tasks */ currentTask = 1; currentStkTop = task1StkTop; flushTLB(); } } /**************************************************************/ void main(void) { currentTask = 0; currentStkTop = task0StkTop; printf("\n"); printf("OS: initializing interrupts\n"); initInterrupts(); setISR(20, trapISR); setISR(21, missISR); setISR(14, timerISR); printf("OS: initializing timer\n"); initTimer(); printf("OS: waiting for interrupt...\n"); enable(); while (1) ; }
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