Data commit

Task/Enumerations/Z80-Assembly/enumerations-1.z80

@@ -0,0 +1,7 @@
+Sunday equ 0
+Monday equ 1
+Tuesday equ 2
+Wednesday equ 3
+Thursday equ 4
+Friday equ 5
+Saturday equ 6

Task/Enumerations/Z80-Assembly/enumerations-2.z80

@@ -0,0 +1,33 @@
+align 8   ;aligns "Days_Of_The_Week" to the next 256-byte boundary. The low byte of "Sunday" will be at memory location &XX00.
+          ;this simplifies the lookup process significantly.
+Days_Of_The_Week:
+    word Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday
+
+Sunday:
+    byte "Sunday",0
+Monday:
+    byte "Monday",0
+Tuesday:
+    byte "Tuesday",0
+Wednesday:
+    byte "Wednesday",0
+Thursday:
+    byte "Thursday",0
+Friday:
+    byte "Friday",0
+Saturday:
+    byte "Saturday",0
+
+;This example will load Friday.
+ld hl,Days_Of_The_Week  ;get base address of table. (Thanks to the align 8, we know that L = 0.)
+ld a,5                  ;0 = Sunday, 1 = Monday, ... 5 = Friday, 6 = Saturday
+add a                   ;Multiply A by 2 (this is faster than SLA A. RLCA would have also worked here)
+ld L,a                  ;since the table was page-aligned it is sufficient to load A directly into L to properly index the table.
+ld e,(hl)               ;get the low byte into E
+inc hl                  ;increment HL to high byte
+ld d,(hl)               ;get the high byte into D
+
+;now DE contains the pointer to "Friday"
+ex de,hl                ;my PrintString routine takes the pointer in HL as the argument so we need to swap DE with HL.
+call PrintString        ;prints a null-terminated string to the screen.
+ret                     ;return to basic