1 # Test out the video mode by filling in the screen with pixels.
 2 #
 3 # To build a disk image:
 4 #   ./translate_subx boot.subx ex2.subx   # emits disk.img
 5 # To run:
 6 #   qemu-system-i386 disk.img
 7 # Or:
 8 #   bochs -f bochsrc                      # bochsrc loads disk.img
 9 
10 == code
11 
12 Entry:
13   # ecx <- start of video memory
14   8b/-> *Video-memory-addr 1/r32/ecx
15 
16   # eax <- final pixel of video memory
17   8d/copy-address *(ecx + 0x0bffff) 0/r32/eax  # 0xbffff = 1024*768 - 1
18 
19   # for each pixel in video memory
20   {
21     39/compare %eax 1/r32/ecx
22     7c/jump-if-< break/disp8
23     # write its column number to it
24     88/byte<- *eax 0/r32/AL
25     48/decrement-eax
26     eb/jump loop/disp8
27   }
28 
29   # hang indefinitely
30   {
31     eb/jump loop/disp8
32   }