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https://github.com/elliotnunn/wedge.git
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95df455703
The Wedge is a C program that, when inserted into a PowerPC ROM, runs just before the NanoKernel. This is very early in the boot process. The Wedge takes this opportunity to rearrange the MacOS address space and make more than 1.5 GB RAM available to applications. Some serious problems remain with this approach, so a "proper" solution to the 1.5 GB RAM limit will take more work. This code was ripped out of the old CDG5 build system and refactored. It it more appropriate to keep the Wedge separate from the real OS code.
123 lines
2.8 KiB
C
123 lines
2.8 KiB
C
#include <stdio.h>
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#include <XCOFF.h>
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#include <MacTypes.h>
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long getblob(char *fileName, char **bufpp)
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{
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FILE *fp;
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FileHdr xc_head;
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fp = fopen(fileName, "rb");
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if(!fp) return -1;
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fread(&xc_head, 1, sizeof xc_head, fp); /* first, is this open file an XCOFF? */
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if(!feof(fp) && xc_head.f_magic == U802TOCMAGIC) { /* YES, XCOFF */
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SectionHdrEntry xc_sec;
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/* we have an xcoff! */
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//if(xc_head.f_nscns != 0) fprintf(stderr, "(XCOFF) %s has %d (!= 1) sections.\n", fileName, xc_head.f_nscns+1);
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fseek(fp, xc_head.f_opthdr, SEEK_CUR); /* skip the aux header */
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fread(&xc_sec, 1, sizeof xc_sec, fp);
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if(feof(fp)) return -2; /* couldnt get a section header entry */
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*bufpp = (char *)malloc(xc_sec.s_size);
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if(!*bufpp) return -3; /* oom */
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fseek(fp, xc_sec.s_scnptr, SEEK_SET);
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fread(*bufpp, 1, xc_sec.s_size, fp);
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if(feof(fp)) return -4; /* could not read section */
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return xc_sec.s_size;
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} else { /* NO, RAW FILE */
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long size;
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fseek(fp, 0, SEEK_END); /* apparently this passes for an idiom in C */
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size = ftell(fp);
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*bufpp = (char *)malloc(size);
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if(!*bufpp) return -3; /* oom */
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fseek(fp, 0, SEEK_SET);
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fread(*bufpp, 1, size, fp);
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if(feof(fp)) return -4; /* could not read section */
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return size;
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}
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}
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int main(int argc, char *argv[])
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{
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FILE *fp;
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char *blob[2];
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long size[2];
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int i;
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if(argc != 3) {
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fprintf(stderr, "Usage: %s ROM WEDGE\n", argv[0]);
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return 1;
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}
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for(i=0; i<2; i++) /* Two or more, use a for. */
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{
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char *fname = argv[i+1];
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size[i] = getblob(fname, &(blob[i]));
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if(size[i] <= 0) {
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fprintf(stderr, "%s: Failed to load: %s\n", argv[0], fname);
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return 1;
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}
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}
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printf("Linking Wedge into %s\n", argv[1]);
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if(size[0] != 0x400000) {
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fprintf(stderr, "%s: ROM is 0x%X bytes, failing\n", argv[0], size[0]);
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return 1;
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}
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if(size[1] > 0x20000) {
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fprintf(stderr, "%s: WEDGE is 0x%X bytes, to large\n", argv[0], size[1]);
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return 1;
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}
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if(blob[0][0x340000] == 0) {
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/* NanoKernel needs to be moved */
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printf("Moving NanoKernel from 310000 to 340000.\n");
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memcpy(blob[0] + 0x340000, blob[0] + 0x310000, 0x20000);
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printf("Erasing original NanoKernel location.\n");
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memset(blob[0] + 0x310000, 0, 0x20000);
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} else {
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printf("NanoKernel already moved to 340000. Erasing old Wedge.\n");
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memset(blob[0] + 0x310000, 0, 0x20000);
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}
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printf("Copying Wedge (0x%X bytes).\n", size[1]);
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memcpy(blob[0] + 0x310000, blob[1], size[1]);
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printf("Writing out.\n");
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fp = fopen(argv[1], "wb");
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if(!fp) {
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fprintf(stderr, "%s: Failed to open for writing: %s\n", argv[0], argv[1]);
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return 1;
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}
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if(fwrite(blob[0], size[0], 1, fp) != 1) {
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fprintf(stderr, "%s: Failed to write: %s\n", argv[0], argv[1]);
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return 1;
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}
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if(fclose(fp)) {
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fprintf(stderr, "%s: Failed to close: %s\n", argv[0], argv[1]);
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return 1;
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}
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return 0;
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}
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