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https://opencores.org/ocsvn/eco32/eco32/trunk
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[/] [eco32/] [trunk/] [sim/] [disk.c] - Rev 229
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/* * disk.c -- disk simulation */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <setjmp.h> #include "common.h" #include "console.h" #include "error.h" #include "except.h" #include "cpu.h" #include "timer.h" #include "disk.h" static Bool debug = false; static FILE *diskImage; static long totalSectors; static Word diskCtrl; static Word diskCnt; static Word diskSct; static Word diskCap; static Byte diskBuffer[8 * SECTOR_SIZE]; static long lastSct; static Word readWord(Byte *p) { Word data; data = ((Word) *(p + 0)) << 24 | ((Word) *(p + 1)) << 16 | ((Word) *(p + 2)) << 8 | ((Word) *(p + 3)) << 0; return data; } static void writeWord(Byte *p, Word data) { *(p + 0) = (Byte) (data >> 24); *(p + 1) = (Byte) (data >> 16); *(p + 2) = (Byte) (data >> 8); *(p + 3) = (Byte) (data >> 0); } static void diskCallback(int n) { int numScts; if (debug) { cPrintf("\n**** DISK CALLBACK, n = %d ****\n", n); } if (n == 0) { /* startup time expired */ diskCap = totalSectors; diskCtrl |= DISK_READY; return; } /* disk read or write */ numScts = ((diskCnt - 1) & 0x07) + 1; if (diskCap != 0 && diskSct < diskCap && diskSct + numScts <= diskCap) { /* do the transfer */ if (fseek(diskImage, diskSct * SECTOR_SIZE, SEEK_SET) != 0) { error("cannot position to sector in disk image"); } if (diskCtrl & DISK_WRT) { /* buffer --> disk */ if (fwrite(diskBuffer, SECTOR_SIZE, numScts, diskImage) != numScts) { error("cannot write to disk image"); } } else { /* disk --> buffer */ if (fread(diskBuffer, SECTOR_SIZE, numScts, diskImage) != numScts) { error("cannot read from disk image"); } } lastSct = (long) diskSct + (long) numScts - 1; } else { /* sectors requested exceed disk capacity */ /* or we have no disk at all */ diskCtrl |= DISK_ERR; } diskCtrl &= ~DISK_STRT; diskCtrl |= DISK_DONE; if (diskCtrl & DISK_IEN) { /* raise disk interrupt */ cpuSetInterrupt(IRQ_DISK); } } Word diskRead(Word addr) { Word data; if (debug) { cPrintf("\n**** DISK READ from 0x%08X", addr); } if (addr == DISK_CTRL) { data = diskCtrl; } else if (addr == DISK_CNT) { data = diskCnt; } else if (addr == DISK_SCT) { data = diskSct; } else if (addr == DISK_CAP) { data = diskCap; } else if (addr & 0x80000) { /* buffer access */ data = readWord(diskBuffer + (addr & 0x0FFC)); } else { /* illegal register */ throwException(EXC_BUS_TIMEOUT); } if (debug) { cPrintf(", data = 0x%08X ****\n", data); } return data; } void diskWrite(Word addr, Word data) { long delta; if (debug) { cPrintf("\n**** DISK WRITE to 0x%08X, data = 0x%08X ****\n", addr, data); } if (addr == DISK_CTRL) { if (data & DISK_WRT) { diskCtrl |= DISK_WRT; } else { diskCtrl &= ~DISK_WRT; } if (data & DISK_IEN) { diskCtrl |= DISK_IEN; } else { diskCtrl &= ~DISK_IEN; } if (data & DISK_STRT) { diskCtrl |= DISK_STRT; diskCtrl &= ~DISK_ERR; diskCtrl &= ~DISK_DONE; /* only start a disk operation if disk is present */ if (diskCap != 0) { delta = labs((long) diskSct - lastSct); if (delta > diskCap) { delta = diskCap; } timerStart(DISK_DELAY_USEC + (delta * DISK_SEEK_USEC) / diskCap, diskCallback, 1); } } else { diskCtrl &= ~DISK_STRT; if (data & DISK_ERR) { diskCtrl |= DISK_ERR; } else { diskCtrl &= ~DISK_ERR; } if (data & DISK_DONE) { diskCtrl |= DISK_DONE; } else { diskCtrl &= ~DISK_DONE; } } if ((diskCtrl & DISK_IEN) != 0 && (diskCtrl & DISK_DONE) != 0) { /* raise disk interrupt */ cpuSetInterrupt(IRQ_DISK); } else { /* lower disk interrupt */ cpuResetInterrupt(IRQ_DISK); } } else if (addr == DISK_CNT) { diskCnt = data; } else if (addr == DISK_SCT) { diskSct = data; } else if (addr == DISK_CAP) { /* this register is read-only */ throwException(EXC_BUS_TIMEOUT); } else if (addr & 0x80000) { /* buffer access */ writeWord(diskBuffer + (addr & 0x0FFC), data); } else { /* illegal register */ throwException(EXC_BUS_TIMEOUT); } } void diskReset(void) { cPrintf("Resetting Disk...\n"); diskCtrl = 0; diskCnt = 0; diskSct = 0; diskCap = 0; lastSct = 0; if (totalSectors != 0) { cPrintf("Disk of size %ld sectors (%ld bytes) installed.\n", totalSectors, totalSectors * SECTOR_SIZE); timerStart(DISK_START_USEC, diskCallback, 0); } } void diskInit(char *diskImageName) { long numBytes; if (diskImageName == NULL) { /* do not install disk */ diskImage = NULL; totalSectors = 0; } else { /* try to install disk */ diskImage = fopen(diskImageName, "r+b"); if (diskImage == NULL) { error("cannot open disk image '%s'", diskImageName); } fseek(diskImage, 0, SEEK_END); numBytes = ftell(diskImage); fseek(diskImage, 0, SEEK_SET); if (numBytes % SECTOR_SIZE != 0) { error("disk image '%s' does not contain an integral number of sectors", diskImageName); } totalSectors = numBytes / SECTOR_SIZE; } diskReset(); } void diskExit(void) { if (diskImage == NULL) { /* disk not installed */ return; } fclose(diskImage); }
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