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Diffstat (limited to 'baremetal/ex2.hex')
| -rw-r--r-- | baremetal/ex2.hex | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/baremetal/ex2.hex b/baremetal/ex2.hex new file mode 100644 index 00000000..d3fbec8d --- /dev/null +++ b/baremetal/ex2.hex @@ -0,0 +1,29 @@ +# Test out the video mode without running afoul of video memory banking. Fill +# just the first row 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) +b8 ff 04 0a 00 # eax <- 0xa0000 (start of video RAM) + 0x4ff (1279 = final pixel in first row) +# $loop: +3d 00 00 0a 00 # compare eax with 0xa0000 +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 f3 # loop = -13 bytes + +# $break: +e9 fb ff ff ff # hang indefinitely + +# vim:ft=subx |