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--- notes:comporg:spring2025:projects:dapx [2025/03/09 15:42] – [debugmemory function] tkastne1
+++ notes:comporg:spring2025:projects:dapx [2025/03/20 03:15] (current) – [Debug Registers] tkastne1
@@ Line 135: / Line 135: @@
 <code>
-   mov   R1,   0xF0000000  ; Creating the mask
+mov   R1,   0xF0000000  ; Creating the mask
-   and   R1,   R0          ; R0 is the original value
+and   R1,   R0          ; R0 is the original value
 </code>
@@ Line 144: / Line 144: @@
 <code>
-   mov   R2,   R3          ; R3 is the loop count
+mov   R2,   R3          ; R3 is the loop count
-   imul  R2,   -4          ; Left shift bits per nibble
+imul  R2,   -4          ; Left shift bits per nibble
-   mov   R1,   0xF0000000  ; Creating the mask
+mov   R1,   0xF0000000  ; Creating the mask
-   shl   R1,   R2
+shl   R1,   R2
-   and   R1,   R0          ; R0 is the original value
+and   R1,   R0          ; R0 is the original value
 </code>
 ====Shifting====
@@ Line 228: / Line 228: @@
 ======Debug Registers======
-===Printing out R:===
+===Printing out R#:===
+The simplest way to print out the register label would be to separate the singe and double digit registers into to groups
+For registers 0-9 we print 'R' then the register number then ':'
+For registers 10-13 we print 'R' & '1' then the register number minus 10 then ':'
 ===Printing registers===
+Since we want to preserve all of the register values, we push them onto the stack at the start
+Using this we can get the value for each register to print out
+Assuming we push the register 0-13 directly after saving the base pointer we can do the following to get R0:
+<code>
+mov   R0,   [BP - 1] ; Get the value of R0
+push  R0
+mov   R0,  Xpos
+push  R0
+mov   R0,  Ypos
+push  R0
+call  _debug         ; Print out the value of R0 wherever we want
+</code>
+This process can be repeated for all registers
 ===Debugging our debugregs Subroutine===

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