lab2: add livepatching of image in RAM

lab1_v2.S

@@ -8,16 +8,48 @@
     bkpt 0xAB
 .endm
 
+#define A 0x0321
+#define B 0x7005
+#define C 0x0050
+
 .section .text
 
 lab1_v2:
     push.n {lr}
 
-    mov r0, #2073
+    bl calculate_formula_v2
     bl int_to_str
 
     pop.n {pc}
 
+calculate_formula_v2:
+    ldr r0, =A
+    ldr r1, =B
+    ldr r2, =C
+
+    cmp r0, r1
+    bgt gret
+    blt less
+
+    same: @ default
+    add r2, r0, r2, lsr #3
+    add r0, r2, r1
+    b finish
+
+    gret:
+    rsb r0, r0, #192
+    sub r0, r0, r1
+    add r0, r2, r0, lsl #2
+    b finish
+
+    less:
+    orr r1, r1, r2
+    mul r0, r0, r1
+
+    finish:
+    mov r10, r0
+    mov pc, lr
+
 int_to_str:
     mov r3, sp
 
@@ -45,7 +77,6 @@ int_to_str:
     cmp r0, #0
     bne proceed_with_conversion
 
-    finish:
     BKPT_WRITE r3
 
     mov pc, lr

start.S

@@ -19,9 +19,9 @@ __hard_reset__:
 
     bl bootload_v2
 
-
     readloop:
     ldr.n r0, [r7, #8]
+    wfi
     b.n readloop
 
 load_systick_timer:
@@ -53,6 +53,25 @@ bootload_v2:
 
     ldr.n r3, =__ram_start
     add r3, r3, #1
+
+    push {r3}
+    blx r3
+    pop {r3}
+
+    @ patch A
+    ldr r0, =0x707ff64d @ 0xDF7F
+    str r0, [r3, #0xb]
+
+    push {r3}
+    blx r3
+    pop {r3}
+
+    @ patch A and B
+    ldr r0, =0x000af240 @ 0x000A
+    str r0, [r3, #0xb]
+    ldr r0, =0x010af240 @ 0x000A
+    str r0, [r3, #0xf]
+
     blx r3
 
     pop {pc}