path: root/317abort.subx

# Dump a stack trace when you abort.

== code

abort:  # e: (addr array byte)
    # . prologue
    55/push-ebp
    89/<- %ebp 4/r32/esp
    #
    (set-cursor-position-on-real-screen 0 0)
    (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 *(ebp+8) 0xf 0xc)  # 0/real-screen, 0xf/fg=white, 0xc/bg=red
    (dump-call-stack)
    # crash
    {
      eb/jump loop/disp8
    }

dump-call-stack:
    # . prologue
    55/push-ebp
    89/<- %ebp 4/r32/esp
    # . save registers
    50/push-eax
    53/push-ebx
    # traverse the linked list of ebp pointers: https://wiki.osdev.org/Stack_Trace
    8b/-> *ebp 3/r32/ebx
    {
      # loop termination check
      81 7/subop/compare %ebx 0/imm32
      0f 84/jump-if-= break/disp32
      # loop body
      (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "\n" 0 0xc)
      (draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0 *(ebx+4) 0xf 0xc)
      # loop update
      8b/-> *ebx 3/r32/ebx
      #
      e9/jump loop/disp32
    }
$dump-call-stack:end:
    # . restore registers
    5b/pop-to-ebx
    58/pop-to-eax
    # . epilogue
    89/<- %esp 5/r32/ebp
    5d/pop-to-ebp
    c3/return