Data commit

Task/Conditional-structures/68000-Assembly/conditional-structures-1.68000

@@ -0,0 +1,3 @@
+MOVE.L #$FFFFFF00,D0
+CMP.B #0,D0   ;equals zero, so zero flag is set.
+CMP.W #0,D0   ;doesn't equals zero, so zero flag is clear.

Task/Conditional-structures/68000-Assembly/conditional-structures-2.68000

@@ -0,0 +1,3 @@
+BTST #7,D0  ;test bit 7 of D0, i.e. the leftmost bit in the rightmost byte.
+BNE goHere  ;if that bit is 1, branch to "goHere"
+BEQ goThere ;if that bit is 0, branch to "goThere"

Task/Conditional-structures/68000-Assembly/conditional-structures-3.68000

@@ -0,0 +1,5 @@
+CMP.L #3,D0   ;this works with any size operands, not just L.
+BNE doNothing
+ADD.L #7,D0
+doNothing:
+;rest of program

Task/Conditional-structures/68000-Assembly/conditional-structures-4.68000

@@ -0,0 +1,34 @@
+SwitchCase:
+DC.L foo,bar,baz,default ;case 0, case 1, case 2, case 3. (Case 0,1,2 are the "valid" cases.)
+; D0 is the case selector variable (byte-sized)
+doSwitchCase:       ;this is a subroutine that gets called elsewhere.
+LEA SwitchCase,A0
+
+;this is our bounds check
+CMP.B #3,D0         ;is D0 > 3?
+BLS InBounds        ;if not, keep going
+MOVE.B #3,D0        ;if it is, set it to 3.
+
+
+InBounds:
+LSL.W #2,D0         ;multiply by 4 to index into a table of longs
+MOVE.L (A0,D0),A0   ;deref the pointer and store the desired routine in A0
+MOVE.L A0,-(SP)     ;push it onto the stack
+RTS                 ;"return" to the selected routine. If it ends in an RTS,
+                    ;  that RTS will return to just after "JSR doSwitchCase"
+
+
+foo:
+   ;your code for this case goes here.
+   rts
+
+bar:
+   ;your code for this case goes here.
+   rts
+
+baz:
+   ;your code for this case goes here.
+   rts
+
+default:
+   rts