@ function.s

/* assembly function which uses r4 - r11
   this will break everything */
.global	function1
function1:
    @ trash all the locals
    mov r4, #4
    mov r5, #5
    mov r6, #6
    mov r7, #7
    mov r8, #8
    mov r9, #9
    mov r10, #10
    mov r11, #11
    @ reutrn 42
    mov r0, #42
    mov pc, lr


.global function2
function2:
    @ make space on the stack
    sub sp, sp, #32

    @ push all the regs
    str r4, [sp, #0]
    str r5, [sp, #4]
    str r6, [sp, #8]
    str r7, [sp, #12]
    str r8, [sp, #16]
    str r9, [sp, #20]
    str r10, [sp, #24]
    str r11, [sp, #28]

    @ trash all the locals
    mov r4, #4
    mov r5, #5
    mov r6, #6
    mov r7, #7
    mov r8, #8
    mov r9, #9
    mov r10, #10
    mov r11, #11

    @ restore all regs
    ldr r4, [sp, #0]
    ldr r5, [sp, #4]
    ldr r6, [sp, #8]
    ldr r7, [sp, #12]
    ldr r8, [sp, #16]
    ldr r9, [sp, #20]
    ldr r10, [sp, #24]
    ldr r11, [sp, #28]

    @ clean up stack
    add sp, sp, #32

    @ reutrn 42
    mov r0, #42
    mov pc, lr