Operating-Systems-Laboratory/exhandler.spl at main · vnesh05/Operating-Systems-Laboratory · GitHub

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breakpoint;

[PROCESS_TABLE + [SYSTEM_STATUS_TABLE + 1] * 16 + 9] = -1;

[PROCESS_TABLE + [SYSTEM_STATUS_TABLE + 1] * 16 + 13] = SP;

SP = [PROCESS_TABLE + [SYSTEM_STATUS_TABLE + 1] * 16 + 11] * 512 - 1;

backup;

multipush(EIP);

if ((EC != 0) || ([PROCESS_TABLE + [SYSTEM_STATUS_TABLE + 1] * 16 + 13] == (PTLR * 512 - 1))) then
    if (EC == 0) then
        print "Stack overflow";
    endif;
    if (EC == 1) then
        print "Illegal instruction";
    endif;
    if (EC == 2) then
        print "Illegal memory access";
    endif;
    if (EC == 3) then
        print "Arithmetic Exception";
    endif;

    R1 = 3;
    R2 = [SYSTEM_STATUS_TABLE + 1];
    call MOD_1;

    call MOD_5;
else
alias blockNumber R2;
if (EPN > 3 && EPN < 8) then
    blockNumber = [DISK_MAP_TABLE + [SYSTEM_STATUS_TABLE + 1] * 10 + EPN];

    multipush(R0, R1, R2);
    multipush(EPN);
    R1 = 5;
    R2 = blockNumber;
    call MOD_2;

    multipop(EPN);
    [PAGE_TABLE_BASE + [SYSTEM_STATUS_TABLE + 1] * 20 + 2 * EPN] = R0;
    [PAGE_TABLE_BASE + [SYSTEM_STATUS_TABLE + 1] * 20 + 2 * EPN + 1] = "1100";

    multipop(R0, R1, R2);
else
    multipush(R0, R1, R2);

    R1 = 1;
    call MOD_2;
    [PTBR + 4] = R0;
    [PTBR + 5] = "1110";

    R1 = 1;
    call MOD_2;
    [PTBR + 6] = R0;
    [PTBR + 7] = "1110";

    multipop(R0, R1, R2);
endif;
endif;

[PROCESS_TABLE + [SYSTEM_STATUS_TABLE + 1] * 16 + 9] = 0;

multipop(EIP);

restore;

SP = [PROCESS_TABLE + [SYSTEM_STATUS_TABLE + 1] * 16 + 13];
SP = SP + 1;

[[PTBR + 2 * (SP / 512)] * 512 + (SP % 512)] = EIP;

ireturn;