# Test out the video mode by filling in the screen with pixels.
#
# To run, first prepare a realistically sized disk image:
#   dd if=/dev/zero of=disk.img count=20160  # 512-byte sectors, so 10MB
# Load the disk image:
#   cat baremetal/boot.hex baremetal/ex2.hex  |./bootstrap run apps/hex  > a.bin
#   dd if=a.bin of=disk.img conv=notrunc
# To run:
#   qemu-system-i386 disk.img
# Or:
#   bochs -f apps/boot.bochsrc  # boot.bochsrc loads disk.img

# main:  (address 0x8000)

# ecx <- LFB
8b  # copy *rm32 to r32
  0d  # 00/mod/indirect 001/r32/ecx 101/rm32/use-disp32
  68 7d 00 00 # disp32

# eax <- LFB + 0x13ffff (1280*1024 - 1)
8d  # copy-address rm32 to r32
  81  # 10/mod/*+disp32 000/r32/eax 001/rm32/ecx
  ff ff 13 00  # disp32

# $loop:
# if (eax < ecx) break
39  # compare rm32 with r32
  c8  # 11/mod/direct 001/r32/ecx 000/rm32/eax
7c 06  # break if <
# *eax <- 0xff
c6  # copy imm8 to m8 at r32
  00  # 00/mod/indirect 000/subop 000/eax
  31  # imm32
48  # decrement eax
eb f6  # loop to -10 bytes

# $break:
e9 fb ff ff ff  # hang indefinitely

# vim:ft=subx