From 5671fa02e4f579dde83d8e17dca5c9fd61ff81b6 Mon Sep 17 00:00:00 2001
From: dhwanish-3 <108540722+dhwanish-3@users.noreply.github.com>
Date: Mon, 23 Oct 2023 21:35:52 +0530
Subject: [PATCH] Stage 22 Max memory done*

---
 Stage22/Assgn2/int15.spl   |  11 ++
 Stage22/Assgn2/int15.xsm   |  34 ++++
 Stage22/Assgn2/mod0.spl    |  98 +++++++++++
 Stage22/Assgn2/mod0.xsm    | 239 ++++++++++++++++++++++++++
 Stage22/Assgn2/mod5.spl    |  50 ++++++
 Stage22/Assgn2/mod5.xsm    | 113 ++++++++++++
 Stage22/Assgn2/mod7.spl    | 182 ++++++++++++++++++++
 Stage22/Assgn2/mod7.xsm    | 341 +++++++++++++++++++++++++++++++++++++
 Stage22/Assgn2/timer.spl   |  36 ++++
 Stage22/Assgn2/timer.xsm   |  87 ++++++++++
 xfs-interface/stage22_2.sh |  32 ++++
 11 files changed, 1223 insertions(+)
 create mode 100644 Stage22/Assgn2/int15.spl
 create mode 100644 Stage22/Assgn2/int15.xsm
 create mode 100644 Stage22/Assgn2/mod0.spl
 create mode 100644 Stage22/Assgn2/mod0.xsm
 create mode 100644 Stage22/Assgn2/mod5.spl
 create mode 100644 Stage22/Assgn2/mod5.xsm
 create mode 100644 Stage22/Assgn2/mod7.spl
 create mode 100644 Stage22/Assgn2/mod7.xsm
 create mode 100644 Stage22/Assgn2/timer.spl
 create mode 100644 Stage22/Assgn2/timer.xsm
 create mode 100644 xfs-interface/stage22_2.sh

diff --git a/Stage22/Assgn2/int15.spl b/Stage22/Assgn2/int15.spl
new file mode 100644
index 0000000..54b25f6
--- /dev/null
+++ b/Stage22/Assgn2/int15.spl
@@ -0,0 +1,11 @@
+alias taskManager R0;
+taskManager = SYSTEM_STATUS_TABLE + 24;
+print "contextSwitches:-";
+print [taskManager];
+print "------------";
+print "maxMemUsage:-";
+print [taskManager + 1];
+print "------------";
+print "diskAccesses:-";
+print [taskManager + 2];
+halt;
\ No newline at end of file
diff --git a/Stage22/Assgn2/int15.xsm b/Stage22/Assgn2/int15.xsm
new file mode 100644
index 0000000..ff3915e
--- /dev/null
+++ b/Stage22/Assgn2/int15.xsm
@@ -0,0 +1,34 @@
+MOV R16, 29560
+ADD R16, 24
+MOV R0, R16
+MOV R16, "contextSwitches:-"
+PORT P1, R16
+OUT
+MOV R16, R0
+MOV R16, [R16]
+PORT P1, R16
+OUT
+MOV R16, "------------"
+PORT P1, R16
+OUT
+MOV R16, "maxMemUsage:-"
+PORT P1, R16
+OUT
+MOV R16, R0
+ADD R16, 1
+MOV R16, [R16]
+PORT P1, R16
+OUT
+MOV R16, "------------"
+PORT P1, R16
+OUT
+MOV R16, "diskAccesses:-"
+PORT P1, R16
+OUT
+MOV R16, R0
+ADD R16, 2
+MOV R16, [R16]
+PORT P1, R16
+OUT
+HALT
+HALT
\ No newline at end of file
diff --git a/Stage22/Assgn2/mod0.spl b/Stage22/Assgn2/mod0.spl
new file mode 100644
index 0000000..3361a78
--- /dev/null
+++ b/Stage22/Assgn2/mod0.spl
@@ -0,0 +1,98 @@
+alias functionNum R1;
+alias currentPID R2;
+
+// Acquire Disk
+if (functionNum == 3) then
+    while ([DISK_STATUS_TABLE] == 1) do
+        [PROCESS_TABLE + currentPID * 16 + 4] = WAIT_DISK;
+        multipush(R1, R2);
+        call MOD_5;
+        multipop(R1, R2);
+    endwhile;
+    // disk accesses
+    [SYSTEM_STATUS_TABLE + 26] = [SYSTEM_STATUS_TABLE + 26] + 1;
+    [DISK_STATUS_TABLE] = 1;
+    [DISK_STATUS_TABLE + 4] = currentPID;
+    return;
+endif;
+
+if (functionNum == 6) then // acquire semaphore
+    alias i R3;
+    i = 0;
+    while(i < MAX_SEM_COUNT && [SEMAPHORE_TABLE + 4 * i + 1] != 0) do
+        i = i + 1;
+    endwhile;
+
+    if (i == MAX_SEM_COUNT) then
+        R0 = -1;
+    else
+        [SEMAPHORE_TABLE + 4 * i] = -1;
+        [SEMAPHORE_TABLE + 4 * i + 1] = 1;
+        R0 = i;
+    endif;
+    return;
+endif;
+
+if (functionNum == 7) then // Release semaphore
+    alias semId R2;
+    alias currentPID R3;
+
+    if (currentPID == [SEMAPHORE_TABLE + semId * 4]) then
+        [SEMAPHORE_TABLE + semId * 4] = -1;
+        alias i R4;
+
+        i = 0;
+        while (i < 16) do
+            if ([PROCESS_TABLE + i * 16 + 4] == WAIT_SEMAPHORE && [PROCESS_TABLE + i * 16 + 5] == semId) then
+                [PROCESS_TABLE + i * 16 + 4] = READY;
+                [PROCESS_TABLE + i * 16 + 5] = -1;
+            endif;
+            i = i + 1;
+        endwhile;
+
+        [SEMAPHORE_TABLE + 4 * semId + 1] = [SEMAPHORE_TABLE + 4 * semId + 1] - 1;
+    endif;
+    return;
+endif;
+
+// Acquire Terminal
+if (functionNum == 8) then
+    while ([TERMINAL_STATUS_TABLE] != 0) do
+        [PROCESS_TABLE + currentPID * 16 + 4] = WAIT_TERMINAL;
+        multipush(R1, R2);
+
+        call MOD_5;
+
+        multipop(R1, R2);
+    endwhile;
+
+    [TERMINAL_STATUS_TABLE] = 1;
+    [TERMINAL_STATUS_TABLE + 1] = currentPID;
+    return;
+endif;
+
+// Release Terminal
+if (functionNum == 9) then
+    if (currentPID != [TERMINAL_STATUS_TABLE + 1]) then
+        alias returnValue R0;
+        returnValue = -1;
+        return; 
+    else
+        [TERMINAL_STATUS_TABLE] = 0;
+        alias i R3;
+        i = 0;
+        while (i < 16) do
+            if ([PROCESS_TABLE + i * 16 + 4] == WAIT_TERMINAL) then
+                [PROCESS_TABLE + 16 * i + 4] = READY;
+            endif;
+            i = i + 1;
+        endwhile;
+        alias returnValue R0;
+        returnValue = 0;
+        return;
+    endif;
+else
+    alias returnValue R0;
+    returnValue = -1;
+    return;
+endif;
\ No newline at end of file
diff --git a/Stage22/Assgn2/mod0.xsm b/Stage22/Assgn2/mod0.xsm
new file mode 100644
index 0000000..c59328a
--- /dev/null
+++ b/Stage22/Assgn2/mod0.xsm
@@ -0,0 +1,239 @@
+MOV R16, 3
+EQ R16, R1
+JZ R16, _L1
+_L3:
+MOV R16, 29552
+MOV R16, [R16]
+MOV R17, 1
+EQ R16, R17
+JZ R16, _L4
+MOV R16, 28672
+MOV R17, R2
+MUL R17, 16
+ADD R16, R17
+ADD R16, 4
+MOV [R16], 5
+PUSH R1
+PUSH R2
+CALL 25600
+POP R2
+POP R1
+JMP _L3
+_L4:
+MOV R16, 29560
+ADD R16, 26
+MOV R17, 29560
+ADD R17, 26
+MOV R17, [R17]
+ADD R17, 1
+MOV [R16], R17
+MOV [29552], 1
+MOV R16, 29552
+ADD R16, 4
+MOV [R16], R2
+RET
+JMP _L2
+_L1:
+_L2:
+MOV R16, 6
+EQ R16, R1
+JZ R16, _L5
+MOV R3, 0
+_L7:
+MOV R16, 32
+GT R16, R3
+MOV R17, 29056
+MOV R18, 4
+MUL R18, R3
+ADD R17, R18
+ADD R17, 1
+MOV R17, [R17]
+MOV R18, 0
+NE R17, R18
+MUL R16, R17
+JZ R16, _L8
+MOV R16, R3
+ADD R16, 1
+MOV R3, R16
+JMP _L7
+_L8:
+MOV R16, 32
+EQ R16, R3
+JZ R16, _L9
+MOV R0, -1
+JMP _L10
+_L9:
+MOV R16, 29056
+MOV R17, 4
+MUL R17, R3
+ADD R16, R17
+MOV [R16], -1
+MOV R16, 29056
+MOV R17, 4
+MUL R17, R3
+ADD R16, R17
+ADD R16, 1
+MOV [R16], 1
+MOV R0, R3
+_L10:
+RET
+JMP _L6
+_L5:
+_L6:
+MOV R16, 7
+EQ R16, R1
+JZ R16, _L11
+MOV R16, 29056
+MOV R17, R2
+MUL R17, 4
+ADD R16, R17
+MOV R16, [R16]
+EQ R16, R3
+JZ R16, _L13
+MOV R16, 29056
+MOV R17, R2
+MUL R17, 4
+ADD R16, R17
+MOV [R16], -1
+MOV R4, 0
+_L15:
+MOV R16, 16
+GT R16, R4
+JZ R16, _L16
+MOV R16, 28672
+MOV R17, R4
+MUL R17, 16
+ADD R16, R17
+ADD R16, 4
+MOV R16, [R16]
+MOV R17, 10
+EQ R16, R17
+MOV R17, 28672
+MOV R18, R4
+MUL R18, 16
+ADD R17, R18
+ADD R17, 5
+MOV R17, [R17]
+EQ R17, R2
+MUL R16, R17
+JZ R16, _L17
+MOV R16, 28672
+MOV R17, R4
+MUL R17, 16
+ADD R16, R17
+ADD R16, 4
+MOV [R16], 1
+MOV R16, 28672
+MOV R17, R4
+MUL R17, 16
+ADD R16, R17
+ADD R16, 5
+MOV [R16], -1
+JMP _L18
+_L17:
+_L18:
+MOV R16, R4
+ADD R16, 1
+MOV R4, R16
+JMP _L15
+_L16:
+MOV R16, 29056
+MOV R17, 4
+MUL R17, R2
+ADD R16, R17
+ADD R16, 1
+MOV R17, 29056
+MOV R18, 4
+MUL R18, R2
+ADD R17, R18
+ADD R17, 1
+MOV R17, [R17]
+SUB R17, 1
+MOV [R16], R17
+JMP _L14
+_L13:
+_L14:
+RET
+JMP _L12
+_L11:
+_L12:
+MOV R16, 8
+EQ R16, R1
+JZ R16, _L19
+_L21:
+MOV R16, 29568
+MOV R16, [R16]
+MOV R17, 0
+NE R16, R17
+JZ R16, _L22
+MOV R16, 28672
+MOV R17, R2
+MUL R17, 16
+ADD R16, R17
+ADD R16, 4
+MOV [R16], 8
+PUSH R1
+PUSH R2
+CALL 25600
+POP R2
+POP R1
+JMP _L21
+_L22:
+MOV [29568], 1
+MOV R16, 29568
+ADD R16, 1
+MOV [R16], R2
+RET
+JMP _L20
+_L19:
+_L20:
+MOV R16, 9
+EQ R16, R1
+JZ R16, _L23
+MOV R16, 29568
+ADD R16, 1
+MOV R16, [R16]
+NE R16, R2
+JZ R16, _L25
+MOV R0, -1
+RET
+JMP _L26
+_L25:
+MOV [29568], 0
+MOV R3, 0
+_L27:
+MOV R16, 16
+GT R16, R3
+JZ R16, _L28
+MOV R16, 28672
+MOV R17, R3
+MUL R17, 16
+ADD R16, R17
+ADD R16, 4
+MOV R16, [R16]
+MOV R17, 8
+EQ R16, R17
+JZ R16, _L29
+MOV R16, 28672
+MOV R17, 16
+MUL R17, R3
+ADD R16, R17
+ADD R16, 4
+MOV [R16], 1
+JMP _L30
+_L29:
+_L30:
+MOV R16, R3
+ADD R16, 1
+MOV R3, R16
+JMP _L27
+_L28:
+MOV R0, 0
+RET
+_L26:
+JMP _L24
+_L23:
+MOV R0, -1
+RET
+_L24:
+HALT
\ No newline at end of file
diff --git a/Stage22/Assgn2/mod5.spl b/Stage22/Assgn2/mod5.spl
new file mode 100644
index 0000000..04b7ab1
--- /dev/null
+++ b/Stage22/Assgn2/mod5.spl
@@ -0,0 +1,50 @@
+alias currentPID R0;
+alias process_table_entry R1;
+
+currentPID = [SYSTEM_STATUS_TABLE + 1];
+process_table_entry = PROCESS_TABLE + 16 * currentPID;
+
+multipush(BP);
+
+[process_table_entry + 12] = SP % 512;
+[process_table_entry + 14] = PTBR;
+[process_table_entry + 15] = PTLR;
+
+alias i R2;
+alias state R3;
+alias newPID R4;
+
+newPID = 0;
+i = currentPID + 1;
+while (i < 16) do
+    state = [PROCESS_TABLE + i * 16 + 4];
+    if (state == READY || state == CREATED) then
+        newPID = i;
+        break;
+    endif;
+    i = i + 1;
+endwhile;
+
+// context switches
+[SYSTEM_STATUS_TABLE + 24] = [SYSTEM_STATUS_TABLE + 24] + 1;
+
+process_table_entry = PROCESS_TABLE + (newPID * 16);
+SP = [process_table_entry + 11] * 512 + [process_table_entry + 12];
+PTBR = [process_table_entry + 14];
+PTLR = [process_table_entry + 15];
+
+[SYSTEM_STATUS_TABLE + 1] = newPID;
+
+if (state == CREATED) then
+    SP = [process_table_entry + 13];
+    BP = [[process_table_entry + 11] * 512];
+    [process_table_entry + 4] = RUNNING;
+    [process_table_entry + 9] = 0; // mode flag
+    ireturn;
+endif;
+
+[process_table_entry + 4] = RUNNING;
+
+multipop(BP);
+
+return;
\ No newline at end of file
diff --git a/Stage22/Assgn2/mod5.xsm b/Stage22/Assgn2/mod5.xsm
new file mode 100644
index 0000000..75f2e04
--- /dev/null
+++ b/Stage22/Assgn2/mod5.xsm
@@ -0,0 +1,113 @@
+MOV R16, 29560
+ADD R16, 1
+MOV R16, [R16]
+MOV R0, R16
+MOV R16, 28672
+MOV R17, 16
+MUL R17, R0
+ADD R16, R17
+MOV R1, R16
+PUSH BP
+MOV R16, R1
+ADD R16, 12
+MOV R17, SP
+MOD R17, 512
+MOV [R16], R17
+MOV R16, R1
+ADD R16, 14
+MOV [R16], PTBR
+MOV R16, R1
+ADD R16, 15
+MOV [R16], PTLR
+MOV R4, 0
+MOV R16, R0
+ADD R16, 1
+MOV R2, R16
+_L1:
+MOV R16, 16
+GT R16, R2
+JZ R16, _L2
+MOV R16, 28672
+MOV R17, R2
+MUL R17, 16
+ADD R16, R17
+ADD R16, 4
+MOV R16, [R16]
+MOV R3, R16
+MOV R16, 1
+EQ R16, R3
+MOV R17, 3
+EQ R17, R3
+ADD R16, R17
+JZ R16, _L3
+MOV R4, R2
+JMP _L2
+JMP _L4
+_L3:
+_L4:
+MOV R16, R2
+ADD R16, 1
+MOV R2, R16
+JMP _L1
+_L2:
+MOV R16, 29560
+ADD R16, 24
+MOV R17, 29560
+ADD R17, 24
+MOV R17, [R17]
+ADD R17, 1
+MOV [R16], R17
+MOV R16, 28672
+MOV R17, R4
+MUL R17, 16
+ADD R16, R17
+MOV R1, R16
+MOV R16, R1
+ADD R16, 11
+MOV R16, [R16]
+MUL R16, 512
+MOV R17, R1
+ADD R17, 12
+MOV R17, [R17]
+ADD R16, R17
+MOV SP, R16
+MOV R16, R1
+ADD R16, 14
+MOV R16, [R16]
+MOV PTBR, R16
+MOV R16, R1
+ADD R16, 15
+MOV R16, [R16]
+MOV PTLR, R16
+MOV R16, 29560
+ADD R16, 1
+MOV [R16], R4
+MOV R16, 3
+EQ R16, R3
+JZ R16, _L5
+MOV R16, R1
+ADD R16, 13
+MOV R16, [R16]
+MOV SP, R16
+MOV R16, R1
+ADD R16, 11
+MOV R16, [R16]
+MUL R16, 512
+MOV R16, [R16]
+MOV BP, R16
+MOV R16, R1
+ADD R16, 4
+MOV [R16], 2
+MOV R16, R1
+ADD R16, 9
+MOV [R16], 0
+IRET
+JMP _L6
+_L5:
+_L6:
+MOV R16, R1
+ADD R16, 4
+MOV [R16], 2
+POP BP
+RET
+HALT
\ No newline at end of file
diff --git a/Stage22/Assgn2/mod7.spl b/Stage22/Assgn2/mod7.spl
new file mode 100644
index 0000000..ffd4268
--- /dev/null
+++ b/Stage22/Assgn2/mod7.spl
@@ -0,0 +1,182 @@
+// exhandler
+loadi(2, 15);
+loadi(3, 16);
+
+// timer interrupt
+loadi(4, 17);
+loadi(5, 18);
+
+// write interrupt
+loadi(16, 29);
+loadi(17, 30);
+
+// int 10
+loadi(22, 35);
+loadi(23, 36);
+
+// int 8 (fork)
+loadi(18, 31);
+loadi(19, 32);
+
+// Library
+loadi(63, 13);
+loadi(64, 14);
+
+// init
+loadi(65, 7);
+loadi(66, 8);
+
+// module 5
+loadi(50, 63);
+loadi(51, 64);
+
+// module 0
+loadi(40, 53);
+loadi(41, 54);
+
+// module 4
+loadi(48, 61);
+loadi(49, 62);
+
+// console interrupt
+loadi(8, 21);
+loadi(9, 22);
+
+// int 6
+loadi(14, 27);
+loadi(15, 28);
+
+// int 9
+loadi(20, 33);
+loadi(21, 34);
+
+// int 11
+loadi(24, 37);
+loadi(25, 38);
+
+// int 13
+loadi(28, 41);
+loadi(29, 42);
+
+// int 14
+loadi(30, 43);
+loadi(31, 44);
+
+// int 15
+loadi(32, 45);
+loadi(33, 46);
+
+// module 1
+loadi(42, 55);
+loadi(43, 56);
+
+// module 2
+loadi(44, 57);
+loadi(45, 58);
+
+// inode user table
+loadi(59, 3);
+loadi(60, 4);
+
+// disk interrupt
+loadi(6, 19);
+loadi(7, 20);
+
+// disk free list
+loadi(61, 2);
+
+// memory free list initialization
+alias i R0;
+i = 0;
+while (i < 128) do
+    if (i < 76) then
+        [MEMORY_FREE_LIST  + i] = 1;
+    else
+        [MEMORY_FREE_LIST + i] = 0;
+    endif;
+    i = i + 1;
+endwhile;
+
+[MEMORY_FREE_LIST + 76] = 1;
+[MEMORY_FREE_LIST + 77] = 1;
+[MEMORY_FREE_LIST + 78] = 1;
+[MEMORY_FREE_LIST + 79] = 1;
+[MEMORY_FREE_LIST + 80] = 1;
+[MEMORY_FREE_LIST + 81] = 1;
+[MEMORY_FREE_LIST + 82] = 1;
+
+PTBR = PAGE_TABLE_BASE + 20;
+PTLR = 10;
+
+[PTBR + 0] = 63;
+[PTBR + 1] = "0100";
+[PTBR + 2] = 64;
+[PTBR + 3] = "0100";
+[PTBR + 4] = 78;
+[PTBR + 5] = "0110";
+[PTBR + 6] = 79;
+[PTBR + 7] = "0110";
+[PTBR + 8] = 65;
+[PTBR + 9] = "0100";
+[PTBR + 10] = 66;
+[PTBR + 11] = "0100";
+[PTBR + 12] = -1;
+[PTBR + 13] = "0000";
+[PTBR + 14] = -1;
+[PTBR + 15] = "0000";
+[PTBR + 16] = 76;
+[PTBR + 17] = "0110";
+[PTBR + 18] = 77;
+[PTBR + 19] = "0110";
+
+[PROCESS_TABLE + 16 + 1] = 1;
+[PROCESS_TABLE + 16 + 11] = 80;
+[PROCESS_TABLE + 16 + 12] = 0;
+[PROCESS_TABLE + 16 + 13] = 8 * 512;
+[PROCESS_TABLE + 16 + 14] = PTBR;
+[PROCESS_TABLE + 16 + 15] = PTLR;
+[PROCESS_TABLE + 16 + 4] = CREATED;
+[76 * 512] = [65 * 512 + 1];
+
+// per-process resource table for init
+i = 1;
+while (i < 9) do
+    [([PROCESS_TABLE + 16 + 11] + 1) * 512 - 2 * i] = -1;
+    i = i + 1;
+endwhile;
+
+// disk map table initialization for init
+
+[DISK_MAP_TABLE + 10 + 2] = -1;
+[DISK_MAP_TABLE + 10 + 3] = -1;
+[DISK_MAP_TABLE + 10 + 4] = 7;
+[DISK_MAP_TABLE + 10 + 5] = 8;
+[DISK_MAP_TABLE + 10 + 6] = -1;
+[DISK_MAP_TABLE + 10 + 7] = -1;
+[DISK_MAP_TABLE + 10 + 8] = -1;
+[DISK_MAP_TABLE + 10 + 9] = -1;
+
+i = 2;
+while (i < 16) do
+    [PROCESS_TABLE + 16 * i + 4] = TERMINATED;
+    i = i + 1;
+endwhile;
+
+[TERMINAL_STATUS_TABLE] = 0;
+[DISK_STATUS_TABLE] = 0;
+[SYSTEM_STATUS_TABLE + 0] = 0;
+[SYSTEM_STATUS_TABLE + 2] = 45;
+[SYSTEM_STATUS_TABLE + 3] = 0;
+[SYSTEM_STATUS_TABLE + 24] = 0; // context switches
+[SYSTEM_STATUS_TABLE + 25] = 0; // max memory usage
+[SYSTEM_STATUS_TABLE + 26] = 0; // disk accesses
+
+// initialization of semaphore table
+i = 0;
+while (i < MAX_SEM_COUNT) do
+    [SEMAPHORE_TABLE + i * 4] = -1;
+    [SEMAPHORE_TABLE + i * 4 + 1] = 0;
+    i = i + 1;
+endwhile;
+
+return;
\ No newline at end of file
diff --git a/Stage22/Assgn2/mod7.xsm b/Stage22/Assgn2/mod7.xsm
new file mode 100644
index 0000000..2b9ffa2
--- /dev/null
+++ b/Stage22/Assgn2/mod7.xsm
@@ -0,0 +1,341 @@
+MOV R16, 2
+LOADI R16, 15
+MOV R16, 3
+LOADI R16, 16
+MOV R16, 4
+LOADI R16, 17
+MOV R16, 5
+LOADI R16, 18
+MOV R16, 16
+LOADI R16, 29
+MOV R16, 17
+LOADI R16, 30
+MOV R16, 22
+LOADI R16, 35
+MOV R16, 23
+LOADI R16, 36
+MOV R16, 18
+LOADI R16, 31
+MOV R16, 19
+LOADI R16, 32
+MOV R16, 63
+LOADI R16, 13
+MOV R16, 64
+LOADI R16, 14
+MOV R16, 65
+LOADI R16, 7
+MOV R16, 66
+LOADI R16, 8
+MOV R16, 50
+LOADI R16, 63
+MOV R16, 51
+LOADI R16, 64
+MOV R16, 40
+LOADI R16, 53
+MOV R16, 41
+LOADI R16, 54
+MOV R16, 48
+LOADI R16, 61
+MOV R16, 49
+LOADI R16, 62
+MOV R16, 8
+LOADI R16, 21
+MOV R16, 9
+LOADI R16, 22
+MOV R16, 14
+LOADI R16, 27
+MOV R16, 15
+LOADI R16, 28
+MOV R16, 20
+LOADI R16, 33
+MOV R16, 21
+LOADI R16, 34
+MOV R16, 24
+LOADI R16, 37
+MOV R16, 25
+LOADI R16, 38
+MOV R16, 28
+LOADI R16, 41
+MOV R16, 29
+LOADI R16, 42
+MOV R16, 30
+LOADI R16, 43
+MOV R16, 31
+LOADI R16, 44
+MOV R16, 32
+LOADI R16, 45
+MOV R16, 33
+LOADI R16, 46
+MOV R16, 42
+LOADI R16, 55
+MOV R16, 43
+LOADI R16, 56
+MOV R16, 44
+LOADI R16, 57
+MOV R16, 45
+LOADI R16, 58
+MOV R16, 59
+LOADI R16, 3
+MOV R16, 60
+LOADI R16, 4
+MOV R16, 6
+LOADI R16, 19
+MOV R16, 7
+LOADI R16, 20
+MOV R16, 61
+LOADI R16, 2
+MOV R0, 0
+_L1:
+MOV R16, 128
+GT R16, R0
+JZ R16, _L2
+MOV R16, 76
+GT R16, R0
+JZ R16, _L3
+MOV R16, 29184
+ADD R16, R0
+MOV [R16], 1
+JMP _L4
+_L3:
+MOV R16, 29184
+ADD R16, R0
+MOV [R16], 0
+_L4:
+MOV R16, R0
+ADD R16, 1
+MOV R0, R16
+JMP _L1
+_L2:
+MOV R16, 29184
+ADD R16, 76
+MOV [R16], 1
+MOV R16, 29184
+ADD R16, 77
+MOV [R16], 1
+MOV R16, 29184
+ADD R16, 78
+MOV [R16], 1
+MOV R16, 29184
+ADD R16, 79
+MOV [R16], 1
+MOV R16, 29184
+ADD R16, 80
+MOV [R16], 1
+MOV R16, 29184
+ADD R16, 81
+MOV [R16], 1
+MOV R16, 29184
+ADD R16, 82
+MOV [R16], 1
+MOV R16, 29696
+ADD R16, 20
+MOV PTBR, R16
+MOV PTLR, 10
+MOV R16, PTBR
+ADD R16, 0
+MOV [R16], 63
+MOV R16, PTBR
+ADD R16, 1
+MOV [R16], "0100"
+MOV R16, PTBR
+ADD R16, 2
+MOV [R16], 64
+MOV R16, PTBR
+ADD R16, 3
+MOV [R16], "0100"
+MOV R16, PTBR
+ADD R16, 4
+MOV [R16], 78
+MOV R16, PTBR
+ADD R16, 5
+MOV [R16], "0110"
+MOV R16, PTBR
+ADD R16, 6
+MOV [R16], 79
+MOV R16, PTBR
+ADD R16, 7
+MOV [R16], "0110"
+MOV R16, PTBR
+ADD R16, 8
+MOV [R16], 65
+MOV R16, PTBR
+ADD R16, 9
+MOV [R16], "0100"
+MOV R16, PTBR
+ADD R16, 10
+MOV [R16], 66
+MOV R16, PTBR
+ADD R16, 11
+MOV [R16], "0100"
+MOV R16, PTBR
+ADD R16, 12
+MOV [R16], -1
+MOV R16, PTBR
+ADD R16, 13
+MOV [R16], "0000"
+MOV R16, PTBR
+ADD R16, 14
+MOV [R16], -1
+MOV R16, PTBR
+ADD R16, 15
+MOV [R16], "0000"
+MOV R16, PTBR
+ADD R16, 16
+MOV [R16], 76
+MOV R16, PTBR
+ADD R16, 17
+MOV [R16], "0110"
+MOV R16, PTBR
+ADD R16, 18
+MOV [R16], 77
+MOV R16, PTBR
+ADD R16, 19
+MOV [R16], "0110"
+MOV R16, 28672
+ADD R16, 16
+ADD R16, 1
+MOV [R16], 1
+MOV R16, 28672
+ADD R16, 16
+ADD R16, 11
+MOV [R16], 80
+MOV R16, 28672
+ADD R16, 16
+ADD R16, 12
+MOV [R16], 0
+MOV R16, 28672
+ADD R16, 16
+ADD R16, 13
+MOV R17, 8
+MUL R17, 512
+MOV [R16], R17
+MOV R16, 28672
+ADD R16, 16
+ADD R16, 14
+MOV [R16], PTBR
+MOV R16, 28672
+ADD R16, 16
+ADD R16, 15
+MOV [R16], PTLR
+MOV R16, 28672
+ADD R16, 16
+ADD R16, 4
+MOV [R16], 3
+MOV R16, 76
+MUL R16, 512
+MOV R17, 65
+MUL R17, 512
+ADD R17, 1
+MOV R17, [R17]
+MOV [R16], R17
+MOV R0, 1
+_L5:
+MOV R16, 9
+GT R16, R0
+JZ R16, _L6
+MOV R16, 28672
+ADD R16, 16
+ADD R16, 11
+MOV R16, [R16]
+ADD R16, 1
+MUL R16, 512
+MOV R17, 2
+MUL R17, R0
+SUB R16, R17
+MOV [R16], -1
+MOV R16, R0
+ADD R16, 1
+MOV R0, R16
+JMP _L5
+_L6:
+MOV R16, 30032
+ADD R16, 10
+ADD R16, 2
+MOV [R16], -1
+MOV R16, 30032
+ADD R16, 10
+ADD R16, 3
+MOV [R16], -1
+MOV R16, 30032
+ADD R16, 10
+ADD R16, 4
+MOV [R16], 7
+MOV R16, 30032
+ADD R16, 10
+ADD R16, 5
+MOV [R16], 8
+MOV R16, 30032
+ADD R16, 10
+ADD R16, 6
+MOV [R16], -1
+MOV R16, 30032
+ADD R16, 10
+ADD R16, 7
+MOV [R16], -1
+MOV R16, 30032
+ADD R16, 10
+ADD R16, 8
+MOV [R16], -1
+MOV R16, 30032
+ADD R16, 10
+ADD R16, 9
+MOV [R16], -1
+MOV R0, 2
+_L7:
+MOV R16, 16
+GT R16, R0
+JZ R16, _L8
+MOV R16, 28672
+MOV R17, 16
+MUL R17, R0
+ADD R16, R17
+ADD R16, 4
+MOV [R16], 4
+MOV R16, R0
+ADD R16, 1
+MOV R0, R16
+JMP _L7
+_L8:
+MOV [29568], 0
+MOV [29552], 0
+MOV R16, 29560
+ADD R16, 0
+MOV [R16], 0
+MOV R16, 29560
+ADD R16, 2
+MOV [R16], 45
+MOV R16, 29560
+ADD R16, 3
+MOV [R16], 0
+MOV R16, 29560
+ADD R16, 24
+MOV [R16], 0
+MOV R16, 29560
+ADD R16, 25
+MOV [R16], 0
+MOV R16, 29560
+ADD R16, 26
+MOV [R16], 0
+MOV R0, 0
+_L9:
+MOV R16, 32
+GT R16, R0
+JZ R16, _L10
+MOV R16, 29056
+MOV R17, R0
+MUL R17, 4
+ADD R16, R17
+MOV [R16], -1
+MOV R16, 29056
+MOV R17, R0
+MUL R17, 4
+ADD R16, R17
+ADD R16, 1
+MOV [R16], 0
+MOV R16, R0
+ADD R16, 1
+MOV R0, R16
+JMP _L9
+_L10:
+RET
+HALT
\ No newline at end of file
diff --git a/Stage22/Assgn2/timer.spl b/Stage22/Assgn2/timer.spl
new file mode 100644
index 0000000..779d05c
--- /dev/null
+++ b/Stage22/Assgn2/timer.spl
@@ -0,0 +1,36 @@
+// Store user SP to UPTR in process table -> 13 th word
+[PROCESS_TABLE + [SYSTEM_STATUS_TABLE + 1] * 16 + 13] = SP;
+
+// Set SP to start of Kernel stack
+SP = [PROCESS_TABLE + [SYSTEM_STATUS_TABLE + 1] * 16 + 11] * 512 - 1;
+
+multipush(R2);
+
+alias prevMemUsage R2;
+prevMemUsage = SYSTEM_STATUS_TABLE + 25;
+if (128 - [SYSTEM_STATUS_TABLE + 2] > [prevMemUsage]) then 
+    [prevMemUsage] = 128 - [SYSTEM_STATUS_TABLE + 2];
+endif;
+
+multipop(R2);
+
+backup;
+
+// obtaining PID of the currently executing process
+alias currentPID R0;
+currentPID = [SYSTEM_STATUS_TABLE + 1];
+
+alias process_table_entry R1;
+process_table_entry = PROCESS_TABLE + currentPID * 16;
+
+[process_table_entry + 4] = READY;
+
+call MOD_5;
+
+restore;
+
+SP = [PROCESS_TABLE + 16 * [SYSTEM_STATUS_TABLE + 1] + 13];
+[PROCESS_TABLE + 16 * [SYSTEM_STATUS_TABLE + 1] + 12] = 0;
+[PROCESS_TABLE + 16 * [SYSTEM_STATUS_TABLE + 1] + 9] = 0;
+
+ireturn;
\ No newline at end of file
diff --git a/Stage22/Assgn2/timer.xsm b/Stage22/Assgn2/timer.xsm
new file mode 100644
index 0000000..ff4de10
--- /dev/null
+++ b/Stage22/Assgn2/timer.xsm
@@ -0,0 +1,87 @@
+MOV R16, 28672
+MOV R17, 29560
+ADD R17, 1
+MOV R17, [R17]
+MUL R17, 16
+ADD R16, R17
+ADD R16, 13
+MOV [R16], SP
+MOV R16, 28672
+MOV R17, 29560
+ADD R17, 1
+MOV R17, [R17]
+MUL R17, 16
+ADD R16, R17
+ADD R16, 11
+MOV R16, [R16]
+MUL R16, 512
+SUB R16, 1
+MOV SP, R16
+PUSH R2
+MOV R16, 29560
+ADD R16, 25
+MOV R2, R16
+MOV R16, 128
+MOV R17, 29560
+ADD R17, 2
+MOV R17, [R17]
+SUB R16, R17
+MOV R17, R2
+MOV R17, [R17]
+GT R16, R17
+JZ R16, _L1
+MOV R16, 128
+MOV R17, 29560
+ADD R17, 2
+MOV R17, [R17]
+SUB R16, R17
+MOV [R2], R16
+JMP _L2
+_L1:
+_L2:
+POP R2
+BACKUP
+MOV R16, 29560
+ADD R16, 1
+MOV R16, [R16]
+MOV R0, R16
+MOV R16, 28672
+MOV R17, R0
+MUL R17, 16
+ADD R16, R17
+MOV R1, R16
+MOV R16, R1
+ADD R16, 4
+MOV [R16], 1
+CALL 25600
+RESTORE
+MOV R16, 28672
+MOV R17, 16
+MOV R18, 29560
+ADD R18, 1
+MOV R18, [R18]
+MUL R17, R18
+ADD R16, R17
+ADD R16, 13
+MOV R16, [R16]
+MOV SP, R16
+MOV R16, 28672
+MOV R17, 16
+MOV R18, 29560
+ADD R18, 1
+MOV R18, [R18]
+MUL R17, R18
+ADD R16, R17
+ADD R16, 12
+MOV [R16], 0
+MOV R16, 28672
+MOV R17, 16
+MOV R18, 29560
+ADD R18, 1
+MOV R18, [R18]
+MUL R17, R18
+ADD R16, R17
+ADD R16, 9
+MOV [R16], 0
+IRET
+HALT
\ No newline at end of file
diff --git a/xfs-interface/stage22_2.sh b/xfs-interface/stage22_2.sh
new file mode 100644
index 0000000..e5909f6
--- /dev/null
+++ b/xfs-interface/stage22_2.sh
@@ -0,0 +1,32 @@
+load --os $HOME/myexpos/Stage13/os_startup.xsm
+load --init $HOME/myexpos/Stage21/Assgn1/shell2.xsm
+load --idle $HOME/myexpos/Stage14/idle.xsm
+load --int=10 $HOME/myexpos/Stage20/exit.xsm
+load --int=11 $HOME/myexpos/Stage21/int11.xsm
+load --int=13 $HOME/myexpos/Stage22/int13.xsm
+load --int=14 $HOME/myexpos/Stage22/int14.xsm
+load --int=15 $HOME/myexpos/Stage22/Assgn2/int15.xsm
+load --int=9 $HOME/myexpos/Stage19/int9.xsm
+load --int=8 $HOME/myexpos/Stage22/fork.xsm
+load --exhandler $HOME/myexpos/Stage21/exhandler.xsm
+load --int=7 $HOME/myexpos/Stage15/int7.xsm
+load --int=6 $HOME/myexpos/Stage16/int6.xsm
+load --int=disk $HOME/myexpos/Stage18/int2.xsm
+load --int=console $HOME/myexpos/Stage16/console_int.xsm
+load --module 5 $HOME/myexpos/Stage22/Assgn2/mod5.xsm
+load --module 7 $HOME/myexpos/Stage22/Assgn2/mod7.xsm
+load --module 0 $HOME/myexpos/Stage22/Assgn2/mod0.xsm
+load --module 1 $HOME/myexpos/Stage22/mod1.xsm
+load --module 2 $HOME/myexpos/Stage19/module_2.xsm
+load --module 4 $HOME/myexpos/Stage18/module_4.xsm
+load --int=timer $HOME/myexpos/Stage22/Assgn2/timer.xsm
+rm test4.xsm
+load --exec $HOME/myexpos/Stage22/Assgn1/test4.xsm
+rm parent.xsm
+load --exec $HOME/myexpos/Stage22/Assgn2/parent.xsm
+rm child.xsm
+load --exec $HOME/myexpos/Stage22/Assgn2/child.xsm
+rm con.xsm
+load --exec $HOME/myexpos/Stage22/Assgn3/con.xsm
+rm seq.xsm
+load --exec $HOME/myexpos/Stage22/Assgn3/seq.xsm
\ No newline at end of file