+/* the quantities involving ctob() are located in the kernel stack.
+/* the others are in the pcb.
+*/
+#define KSP 0
+#define ESP 4
+#define SSP 8
+#define USP (ctob(4)-5*4)
+#define R0 (ctob(4)-19*4)
+#define R1 (ctob(4)-18*4)
+#define R2 (ctob(4)-17*4)
+#define R3 (ctob(4)-16*4)
+#define R4 (ctob(4)-15*4)
+#define R5 (ctob(4)-14*4)
+#define R6 (ctob(4)-13*4)
+#define R7 (ctob(4)-12*4)
+#define R8 (ctob(4)-11*4)
+#define R9 (ctob(4)-10*4)
+#define R10 (ctob(4)-9*4)
+#define R11 (ctob(4)-8*4)
+#define AP (ctob(4)-7*4)
+#define FP (ctob(4)-6*4)
+#define PC (ctob(4)-2*4)
+#define PSL (ctob(4)-1*4)
+#define P0BR 80
+#define P0LR 84
+#define P1BR 88
+#define P1LR 92