diff options
| -rw-r--r-- | baremetal/102keyboard.subx | 42 | ||||
| -rw-r--r-- | baremetal/400.mu | 1 | ||||
| -rw-r--r-- | baremetal/ex3.mu | 31 |
3 files changed, 74 insertions, 0 deletions
diff --git a/baremetal/102keyboard.subx b/baremetal/102keyboard.subx new file mode 100644 index 00000000..7913d449 --- /dev/null +++ b/baremetal/102keyboard.subx @@ -0,0 +1,42 @@ +# check keyboard for a key +# return 0 on no keypress or unrecognized key +read-key: # kbd: (addr keyboard) -> result/eax: byte + # . prologue + 55/push-ebp + 89/<- %ebp 4/r32/esp + # . save registers + 51/push-ecx + # result = 0 + b8/copy-to-eax 0/imm32 + # ecx = keyboard + 8b/-> *(ebp+8) 1/r32/ecx + 81 7/subop/compare %ecx 0/imm32 + { + 75/jump-if-!= break/disp8 + # var read/ecx: byte = keyboard buffer's read index + 8b/-> *0x7dcc 1/r32/CL # keyboard-buffer-read + # var next-key/eax: byte = *(keyboard buffer + ecx) + 8a/byte-> *(ecx+0x7dd0) 0/r32/AL # keyboard-buffer-data + # if (next-key != 0) lock and remove from keyboard-buffer + 81 7/subop/compare %eax 0/imm32 + { + 74/jump-if-= break/disp8 + # TODO: add some instructions in this block to SubX if we ever want to + # use bootstrap on baremetal programs + fa/disable-interrupts + c6 0/subop/copy-byte *(ecx+0x7dd0) 0/imm8 + ff 0/subop/increment *0x7dcc # keyboard-buffer-read + 81 4/subop/and *0x7dcc 0xf/imm32 # keyboard-buffer-read + fb/enable-interrupts + } + # return + eb $read-key:end/disp8 + } + # TODO: fake keyboard +$read-key:end: + # . restore registers + 59/pop-to-ecx + # . epilogue + 89/<- %esp 5/r32/ebp + 5d/pop-to-ebp + c3/return diff --git a/baremetal/400.mu b/baremetal/400.mu index 1121a00a..0f36e3fe 100644 --- a/baremetal/400.mu +++ b/baremetal/400.mu @@ -1 +1,2 @@ sig pixel screen: (addr screen), x: int, y: int, color: int +sig read-key kbd: (addr keyboard) -> _/eax: byte diff --git a/baremetal/ex3.mu b/baremetal/ex3.mu new file mode 100644 index 00000000..21e30466 --- /dev/null +++ b/baremetal/ex3.mu @@ -0,0 +1,31 @@ +# Draw pixels in response to keyboard events, starting from the top-left +# and in raster order. +# +# To build a disk image: +# ./translate_mu_baremetal baremetal/ex3.mu # emits disk.img +# To run: +# qemu-system-i386 disk.img +# Or: +# bochs -f baremetal/boot.bochsrc # boot.bochsrc loads disk.img +# +# Expected output: a new green pixel starting from the top left corner of the +# screen every time you press a key (letter or digit) + +fn main { + var x/ecx: int <- copy 0 + var y/edx: int <- copy 0 + { + var key/eax: byte <- read-key 0 # real keyboard + compare key, 0 + loop-if-= # busy wait + pixel 0, x, y, 0x31 # green + x <- increment + compare x, 0x400 + { + break-if-< + y <- increment + x <- copy 0 + } + loop + } +} |