INSERT[D0LANG]; NOMIDASINIT; TITLE[d0rdt]; *last edited by CT June 10, 1979 SETTASK[17]; RV[REFR,77]; *memory refresh address *The following registers hold the volatile state of the processor on a fault: RV[RXALU,76]; *ALU result and SALUF RV[RXAPC,75]; *APCTask&APC RV[RXCTASK,74]; *CTASK.NCIA RV[RXPPB,73]; *Page,Parity,BootReason RV[RXSTK,72]; *Stackpointer RV[RTMP,71]; *temporary *The following registers are used for D0-Midas communication (RTMP is also used): RV[RWSTAT,70]; *status register RV[RDATA,67]; *holds data *FFault determines how faults will be treated when programs are running. If it is *zero, all faults will be reported to Midas. If FFault is nonzero, the kernel will *send control through location 120 when a fault occurs and PARITY # 0 (faults with *PARITY = 0 are breakpoints). RV[FFAULT,66]; *Registers between 360 and 367 are used by the Midas overlays. The following *registers, used by WriteMI, are also in this range. RV[RADDR,65]; RV[RCNT,64]; RV[STACK4,64]; RV[RW0,63]; RV[STACK3,63]; RV[RW1,62]; RV[STACK2,62]; RV[STACK1,61]; MC[pStk1,361]; *pointer to stack1 RV[STACK0,60]; *Constants for Recv and Send MC[RecvByte,12]; MC[RecvWord,16]; MC[SendByte,21]; MC[SendWord,25]; *The following are at fixed locations in Kernel.mc: UserFault: Return, AT[120]; NextCom: Return, AT[7404]; Send: Return, AT[7460]; Recv: Return, AT[7464]; *d0rdt overlay *Used by Midas to read T for any task. *Notify task n to do the read OverlayArea: RWSTAT ← RecvByte, Call[Recv], at[7500]; *get task number to read stack1 ← T, at[7501]; T ← 7400c, at[7502]; stack1 ← (lsh[stack1,14]) + (T), at[7503]; stack1 ← (stack1) + (111c), at[7504]; *stack1 points to task n, location GetT (7511) RTMP ← pStk1,at[7505]; Stkp ← RTMP, at[7506]; *set stkp to point to stack1 stack0 ← 177400c, at[7507]; *set up stack0 to point to task 17, location 7515 stack0 ← (stack0) + (115c), goto[NotifyBothWays], at[7510]; GetT: Stack&+1 ← T, at[7511]; *Stack1 ← T Stack&-1, at[7512]; *point to return address NotifyBothWays: APC&APCTask ← Stack&-1,at[7513]; return, AT[7514]; T ← Stack1, AT[7515]; *back in task 17, get recovered T RDATA ← T, AT[7516]; nop, AT[7517]; RWSTAT ← SendWord, Call[Send], AT[7520]; *send the word to Midas goto[NextCom], AT[7521]; END;