art $2-$ CPUlator VGA Pixel and Character Buffer

Copy and paste the following code into the CPUlator window:

$.$global $\_$start

$\_$start:

$.$equ ADDR$\_$VGA, $0$xC$8000000/*$ base address for pixel buffer array $/$

$.$equ ADDR$\_$CHAR, $0$xC$9000000/$ base address for character buffer array $/$

$.$equ BLACK, $0$x$0$

$.$equ P$\_$OFFSET, $1032/$ pixel buffer offset $(4,1)$ is x$2+$ y$1024$ so $(8+1024=1032)/$

$.$equ C$\_$OFFSET, $132/$ char buffer offset $(4,1)$ is x $+$ y$128$ so $(4+128=132)/$

ldr r$0,=$ADDR$\_$VGA

ldr r$1,=$ADDR$\_$CHAR

ldr r$2,=$BLACK $/*$ Black pixel $/$

ldr r$3,=$P$\_$OFFSET

mov r$4,$ #$0$x$41/$ ASCII for $\text{'}$A$\text{'}/$

ldr r$5,=$C$\_$OFFSET

strh r$2,[$r$0,$ r$3]/$ Write to pixel buffer, location $(4,1)/$

strb r$4,[$r$1,$ r$5]/$ Write to character buffer, location $(4,1)*/$

$.$end

The code writes to the VGA Pixel buffer $-$ the contents of the buffer are shown on the "VGA Pixel Buffer" window on the right side of the CPUlator window. You can move this window, by clicking on the window top banner and moving it to the top. Also you can zoom in by clicking the configuration icon $($upper left of the window$)$ and adjust the zoom factor to $1.$

Additionally the code also writes the letter $\text{'}$A$\text{'}$ to the character buffer of the VGA display.

After running the above code, you should see the following