Move examples to libvm source base and add symlink to root directory

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/libvm/examples/deadbeef.asm

@@ -0,0 +1,47 @@
+.section data $0x1000 {
+    dead: .u16 $0xDEAD
+    beef: .u16 $0xBEEF
+
+    .export dead
+    .export beef
+}
+
+.section code $0x0 {
+    main:
+        mov %ivt, ivt
+        or %flags, $0b100
+        mov %r0, $0xDEAD
+        shl %r0, $16
+        ; move 32 bits at 'beef' to %r01
+        ; TODO(syntax)
+        mov %r1, (beef)u32
+        or %r0, %r01
+        cmpeq %r0, $0xDEADBEEF
+        ; jump to the address 'end'
+        jnz end
+        mov %status, $1
+    end:
+        div %r0, $0
+        halt
+    .export main
+
+}
+
+.section iv $0x2800 {
+    dz:
+        mov %status, $255
+        halt
+
+    .export dz
+}
+
+.section ivt $0x2000 .. $0x2800 {
+    ivt:
+    .interrupt $1, dz               ; Divide by zero
+
+    .export ivt
+}
+
+.meta {
+    entry: main
+}

src/libvm/examples/factorial.asm

@@ -0,0 +1,28 @@
+.section data $0x1000 {
+    factorial:
+        cmplt %r0, $2
+        jnz factorial_one
+
+        push %r0
+        sub %r0, $1
+        call factorial
+        pop %r0
+        mul %status, %r0
+        jmp factorial_end
+
+    factorial_one:
+        mov %status, $1
+    factorial_end:
+        ret
+
+    main:
+        mov %r0, $5
+        call factorial
+        halt
+
+    .export main
+}
+
+.meta {
+    entry: main
+}

src/libvm/examples/strings.asm

@@ -0,0 +1,30 @@
+.section data $0x1000 .. $0x1100 {
+    zstr: .zstring  "This is a string"
+    str: .string  "This is a string"
+
+    .export zstr
+    .export str
+}
+
+.section code $0x0 {
+    ; Take the length of a zstr without those fancy "function calls" and "stack frames"
+    ; %r0: the input string (in)
+    ; %r1: the return address (in)
+    ; %r2: the length of the string (out)
+
+    zstrlen:
+        mov %r2, %r0
+    ztrlen_loop:
+        cmpeq (%r2)u8, $0
+    zstrlen_end:
+        jmp %r1
+
+    main:
+        halt
+        
+    .export main
+}
+
+.meta {
+    entry: main
+}