feat: working bootloader and basic kernel (just dyes screen green)

Kernel/Source/entry.S

@@ -0,0 +1,22 @@
+.section .text.boot, "ax"
+.global _start
+
+_start:
+    add x1, x0, #64         // x1 = BIFramebuffer
+    ldr x2, [x1]            // x2 = base
+    ldr x3, [x1, #16]       // x3 = width
+    ldr x4, [x1, #24]       // x4 = height
+    
+    mul x5, x3, x4 
+    
+    mov w6, #0x00FF00
+    movk w6, #0x0000, lsl #16 
+
+fill_loop:
+    cbz x5, done
+    str w6, [x2], #4
+    sub x5, x5, #1
+    b fill_loop
+
+done:
+    b done