Initial data commit

Task/Loops-For/Z80-Assembly/loops-for.z80

@@ -0,0 +1,41 @@
+org &4000		; put code at memory address 0x4000
+wr_char equ &bb5a ; write ASCII character in register A to screen
+				; (jumps into CPC ROM)
+
+; put registers on stack so we can return to BASIC later
+push bc
+push de
+push hl
+
+ld b,5		; loop from 5 to 1
+
+row:
+
+push bc	; save outer loop variable
+
+; calculate inner loop limit (6 - outer loop variable)
+ld a,6
+sub b
+ld b,a
+
+column:
+
+ld a,42	; asterisk in ASCII
+call wr_char
+djnz column ; decrement B, jump to label if non-zero
+
+pop bc	; restore outer loop
+
+; print carriage return/line feed
+ld a,13
+call wr_char
+ld a,10
+call wr_char
+
+djnz row
+
+; restore registers
+pop hl
+pop de
+pop bc
+ret	; return to BASIC interpreter