HW4 Initial

2 files changed, 96 insertions, 0 deletions

diff --git a/examprep/Sources/derivative.inc b/examprep/Sources/derivative.inc
new file mode 100644
index 0000000..988343b
--- /dev/null
+++ b/examprep/Sources/derivative.inc
@@ -0,0 +1,10 @@
+
+ ; Note: This file is recreated by the project wizard whenever the MCU is
+ ;       changed and should not be edited by hand
+ ;
+
+			; include derivative specific macros
+            INCLUDE 'mc9s12c32.inc'
+
+		
+
diff --git a/examprep/Sources/main.asm b/examprep/Sources/main.asm
new file mode 100644
index 0000000..ee2c3e1
--- /dev/null
+++ b/examprep/Sources/main.asm
@@ -0,0 +1,86 @@
+**************************************************************************
+* Parameter Declearation Section
+*
+* Export Symbols
+            xdef        pgstart         ; export 'pgstart' symbol
+            absentry    pgstart         ; for assembly entry point
+
+* Symbols and Macros
+PORTA       equ         $0000           ; i/o port A addresses
+DDRA        equ         $0002           ; data direction register for PORTA
+PORTB       equ         $0001           ; i/o port B addresses
+DDRB        equ         $0003           ; data direction register for PORTB
+
+**************************************************************************
+* Data Section: address used [ $3000 to $30FF ] RAM Memory
+*
+            org         $3000           ; Reserved RAM memory starting address
+                                        ;   for Data for CMPEN 472 class
+SOURCE      ds.b        $000C           ; 12 Byte source array
+
+LENSRC      dc.w        $000C           ; Length of the Source Array
+                                        
+DEST        ds.b        $000C           ; 12 Byte destination array
+
+LENDST      dc.w        $000C           ; Length of the destination array
+
+StackSP     dc.w        $3100           ; Address of the stack
+
+*
+**************************************************************************
+* Program Section: address used [ $3100 to $3FFF ] RAM Memory
+*
+            org         $3100           ; Program start address, in RAM
+pgstart     lds         StackSP         ; initialize the stack pointer
+            ldaa        #1              ; Load 1 into A
+            ldx         #SOURCE         ; Load the address of SOURCE into X
+            ldy         LENSRC          ; Load the length of SOURCE into Y
+fillLoop    tbeq        Y,doneLoop      ; If Y==0, jump to done loop
+            staa        1,X+            ; Copy A into address of X, add 1 to X
+            inca                        ; Increment A by 1
+            dey                         ; Decrement Y by 1
+            bra         fillLoop        ; Jump to fillLoop
+doneLoop    jsr         memcpy          ; Call memcpy
+            bra         done
+
+
+**************************************************************************
+* Subroutine Section: address used [ $3100 to $3FFF ] RAM Memory
+*
+
+;*************************************************************************
+; memcpy subroutine
+;
+; This subroutine will copy LENSRC bytes from SOURCE to DEST.
+;
+; Input:                   Two addresses, SOURCE and DEST, 1 word length LENSRC
+; Output:                  LENSRC bytes copied from SOURCE to DEST
+; Registers in use:        D to count the number of bytes copied
+;                          Y to hold the address of the current byte in SOURCE
+;                          X to hold the address of the current byte in DEST
+; Memory locations in use: One word, LENSRC, for the length of bytes to copy
+;                          Two arrays, SOURCE & DEST, to copy from SOURCE to DEST
+;
+memcpy      
+            pshy                        ; Save Y to the stack
+            pshx                        ; Save X to the stack
+            pshd                        ; Save D to the stack
+            ldy         #SOURCE         ; Load the address of the source array into Y
+            ldx         #DEST           ; Load the address of the destination array into X
+            ldd         LENSRC          ; Load the length of the source array into D
+loop        tbeq        D,EXIT          ; If d==0, jump to EXIT
+            movb        Y,X             ; Copy data from address in Y to address in X
+            inx                         ; Increment X by 1
+            iny                         ; Increment Y by 1
+            subd        #1              ; Decrement D by 1
+            bra         loop            ; Branch always to loop
+EXIT        puld                        ; Restore D from the stack
+            pulx                        ; Restore X from the stack
+            puly                        ; Restore Y from the stack
+            rts                         ; Return to caller
+            
+*
+**************************************************************************
+
+done        
+            end                         ; Last line of the file
\ No newline at end of file