Hello-World iOS App in Assembly


	.global _main
	.extern _putchar

	.align 4

	_main:
	; prolog; save fp,lr,x19
	stp x29, x30, [sp, #–0x20]!
	str x19, [sp, #0x10]
	mov x29, sp
	; make space for 2 dword local vars
	sub sp, sp, #0x10
	; save argc/argv
	stp x0, x1, [sp]

	; create autorelease pool and save into x19
	bl _objc_autoreleasePoolPush
	mov x19, x0

	; initialize app delegate class
	bl initAppDelegate

	; create CFString with delegate class name
	mov x0, 0
	adrp x1, str_AppDelegate@PAGE
	add x1, x1, str_AppDelegate@PAGEOFF
	mov x2, 0x0600 ; kCFStringEncodingASCII
	bl _CFStringCreateWithCString

	; x0 = UIApplicationMain(argc, argv, nil, CFSTR(“AppDelegate”));
	mov x3, x0
	ldr x0, [sp]
	ldr x1, [sp, #0x8]
	mov x2, #0
	bl _UIApplicationMain
	mov x7, x0 ; save retval

	; pop autorelease pool
	mov x0, x19
	bl _objc_autoreleasePoolPop

	; epilog
	; restore stack pointer
	add sp, sp, 0x10
	; restore saved registers
	ldr x19, [sp, #0x10]
	ldp x29, x30, [sp], #0x20
	; get retval
	mov x0, x7
	ret

	initAppDelegate:
	; prolog; save fp,lr,x20
	stp x29, x30, [sp, #–0x20]!
	str x20, [sp, #0x10]
	mov x29, sp

	; Class c = objc_allocateClassPair(objc_getClass(“NSObject”), “AppDelegate”, 0);
	adrp x0, str_NSObject@PAGE
	add x0, x0, str_NSObject@PAGEOFF
	bl _objc_getClass
	adrp x1, str_AppDelegate@PAGE
	add x1, x1, str_AppDelegate@PAGEOFF
	mov x2, 0
	bl _objc_allocateClassPair

	; save the class since we’ll clobber x0 several times
	mov x20, x0

	; class_addProtocol(c, objc_getProtocol(“UIApplicationDelegate”));
	adrp x0, str_UIAppDelegate@PAGE
	add x0, x0, str_UIAppDelegate@PAGEOFF
	bl _objc_getProtocol
	mov x1, x0
	mov x0, x20
	bl _class_addProtocol

	; class_addMethod(c, S(“application:didFinishLaunchingWithOptions:”), didFinishLaunching, “B@:@@”);

	adrp x0, str_didFinishLaunchingSel@PAGE
	add x0, x0, str_didFinishLaunchingSel@PAGEOFF
	bl _sel_getUid
	mov x1, x0
	mov x0, x20
	adr x2, didFinishLaunching
	adrp x3, str_typestr@PAGE
	add x3, x3, str_typestr@PAGEOFF
	bl _class_addMethod

	; objc_registerClassPair(c);
	mov x0, x20
	bl _objc_registerClassPair

	; epilog
	ldr x20, [sp, #0x10]
	ldp x29, x30, [sp], #0x20
	ret

	; parameters:
	; x0: self
	; x1: _sel
	; x2: application
	; x3: launchOptions
	didFinishLaunching:
	; prolog, save fp, lr, x19-x22
	stp x29, x30, [sp, #–0x30]!
	stp x19, x20, [sp, #0x10]
	stp x21, x22, [sp, #0x20]
	mov x29, sp
	sub sp, sp, 0x20

	; x19 = @selector(mainScreen)
	adrp x0, str_mainScreen@PAGE
	add x0, x0, str_mainScreen@PAGEOFF
	bl _sel_getUid
	mov x19, x0

	; objc_getClass(“UIScreen”)
	adrp x0, str_UIScreen@PAGE
	add x0, x0, str_UIScreen@PAGEOFF
	bl _objc_getClass

	; x20 = [UIScreen mainScreen]
	mov x1, x19
	bl _objc_msgSend
	mov x20, x0
	; x19 is now free

	; x1 = @selector(bounds)
	adrp x0, str_bounds@PAGE
	add x0, x0, str_bounds@PAGEOFF
	bl _sel_getUid
	mov x1, x0

	; [x20 bounds]
	mov x0, x20
	bl _objc_msgSend

	stp d0, d1, [sp]
	stp d2, d3, [sp, #0x10]

	; x19 = @selector(initWithFrame:)
	adrp x0, str_initWithFrame@PAGE
	add x0, x0, str_initWithFrame@PAGEOFF
	bl _sel_getUid
	mov x19, x0

	; x0 = UIWindow
	adrp x0, str_UIWindow@PAGE
	add x0, x0, str_UIWindow@PAGEOFF
	bl _objc_getClass

	; x0 = class_createInstance(x0)
	mov x1, #0x0
	bl _class_createInstance
	; x0 now has the instance

	; x20 = [x0 initWithFrame:d]
	mov x1, x19 ;initWithFrame
	ldp d0, d1, [sp]
	ldp d2, d3, [sp, #0x10]
	bl _objc_msgSend
	mov x20, x0

	; x19 = @selector(init)
	adrp x0, str_init@PAGE
	add x0, x0, str_init@PAGEOFF
	bl _sel_getUid
	mov x19, x0

	; x0 = UIViewController
	adrp x0, str_UIViewController@PAGE
	add x0, x0, str_UIViewController@PAGEOFF
	bl _objc_getClass

	; x0 = class_createInstance(UIViewController)
	mov x1, #0x0
	bl _class_createInstance
	; x0 now has the instance

	; x21 = [x0 init]
	mov x1, x19 ;init
	bl _objc_msgSend
	mov x21, x0

	; x19 = @selector(yellowColor)
	adrp x0, str_yellowColor@PAGE
	add x0, x0, str_yellowColor@PAGEOFF
	bl _sel_getUid
	mov x19, x0

	; x22 = [UIColor yellowColor]
	adrp x0, str_UIColor@PAGE
	add x0, x0, str_UIColor@PAGEOFF
	bl _objc_getClass
	mov x1, x19
	bl _objc_msgSend
	mov x22, x0

	; x19 = @selector(setBackgroundColor:)
	adrp x0, str_setBackgroundColor@PAGE
	add x0, x0, str_setBackgroundColor@PAGEOFF
	bl _sel_getUid
	mov x19, x0

	; x1 = @selector(view)
	adrp x0, str_view@PAGE
	add x0, x0, str_view@PAGEOFF
	bl _sel_getUid
	mov x1, x0

	; x0 = [[controller view] setBackgroundColor: x22];
	mov x0, x21
	bl _objc_msgSend
	mov x1, x19
	mov x2, x22
	bl _objc_msgSend

	adrp x0, str_setRoot@PAGE
	add x0, x0, str_setRoot@PAGEOFF
	bl _sel_getUid
	mov x1, x0

	; [window setRootViewController:viewController]
	mov x0, x20
	mov x2, x21
	bl _objc_msgSend

	; [x20 makeKeyAndVisible]
	adrp x0, str_makeKeyAndVisible@PAGE
	add x0, x0, str_makeKeyAndVisible@PAGEOFF
	bl _sel_getUid

	mov x1, x0
	mov x0, x20
	bl _objc_msgSend

	; return YES
	mov x0, #0x1

	; epilog
	add sp, sp, 0x20
	ldp x19, x20, [sp, #0x10]
	ldp x21, x22, [sp, #0x20]
	ldp x29, x30, [sp], #0x30
	ret

	.data
	str_NSObject: .asciz “NSObject”
	str_AppDelegate: .asciz “AppDelegate”
	str_UIAppDelegate: .asciz “UIApplicationDelegate”
	str_UIScreen: .asciz “UIScreen”
	str_UIWindow: .asciz “UIWindow”
	str_UIViewController: .asciz “UIViewController”
	str_UIColor: .asciz “UIColor”

	str_typestr: .asciz “B@:@@”
	str_didFinishLaunchingSel: .asciz “application:didFinishLaunchingWithOptions:”
	str_mainScreen: .asciz “mainScreen”
	str_bounds: .asciz “bounds”
	str_initWithFrame: .asciz “initWithFrame:”
	str_makeKeyAndVisible: .asciz “makeKeyAndVisible”
	str_init: .asciz “init”
	str_view: .asciz “view”
	str_setBackgroundColor: .asciz “setBackgroundColor:”
	str_yellowColor: .asciz “yellowColor”
	str_setRoot: .asciz “setRootViewController:”

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Hello-World iOS App in Assembly

Hello-World iOS App in Assembly

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