ref: 05021e057945ef77b585b1835397f59bd3381282
dir: /sys/src/cmd/aux/realemu/loadcom.c/
#include <u.h> #include <libc.h> #include "/386/include/ureg.h" static uchar buf[0xFF01]; void main(int argc, char *argv[]) { struct Ureg u; int fd, rreg, rmem, len; ARGBEGIN { } ARGEND; if(argc == 0){ fprint(2, "usage:\t%s file.com\n", argv0); exits("usage"); } if((fd = open(*argv, OREAD)) < 0) sysfatal("open: %r"); if((rreg = open("/dev/realmode", OWRITE)) < 0) sysfatal("open realmode: %r"); if((rmem = open("/dev/realmodemem", OWRITE)) < 0) sysfatal("open realmodemem: %r"); if((len = readn(fd, buf, sizeof buf)) < 2) sysfatal("file too small"); memset(&u, 0, sizeof u); u.cs = u.ds = u.es = u.fs = u.gs = 0x1000; u.ss = 0x0000; u.sp = 0xfffe; u.pc = 0x0100; seek(rmem, (u.cs<<4) + u.pc, 0); if(write(rmem, buf, len) != len) sysfatal("write mem: %r"); if(write(rreg, &u, sizeof u) != sizeof u) sysfatal("write reg: %r"); }