1*11493Sralph /* setmat.c 4.1 83/03/09 */ 2*11493Sralph /* 3*11493Sralph * setmat: set the value in m[r, c] to nval. 4*11493Sralph */ 5*11493Sralph 6*11493Sralph #include "bit.h" 7*11493Sralph 8*11493Sralph setmat(m, rows, cols, r, c, nval) 9*11493Sralph bitmat m; 10*11493Sralph int rows, cols, r, c, nval; 11*11493Sralph { 12*11493Sralph register int offset, thisbit; 13*11493Sralph 14*11493Sralph if (r<0 || c<0 || r>=rows || c>=cols) { 15*11493Sralph #ifdef TRACE 16*11493Sralph if (trace) 17*11493Sralph fprintf(trace, "setmat range error: (%d, %d) <- %d in a (%d, %d) matrix %x\n", r, c, nval, rows, cols, m); 18*11493Sralph #endif 19*11493Sralph 20*11493Sralph return; 21*11493Sralph } 22*11493Sralph offset = r*((cols+7)>>3) + (c>>3); 23*11493Sralph thisbit = 0x80 >> (c&7); 24*11493Sralph if (nval) 25*11493Sralph m[offset] |= thisbit; 26*11493Sralph else 27*11493Sralph m[offset] &= ~thisbit; 28*11493Sralph } 29