func_fs:
;input
;hl = function to call
;ix = data range to operate over
;de = output area
;b = length of data range

push bc
ld (smc_fs+1),hl
ld a,(ix+0)
smc_fs:
call 0 ;overwritten with the function address passed in HL

ld (de),a
inc ix
inc de
pop bc
djnz func_fs
ret

f:   ;dummy function - returns input as-is
ret

f1:
;returns A times 2
sla a
ret

f2:
;returns A squared
ld b,a
jp square_small
;ret

data1:
db 0,1,2,3

data2
db 2,4,6,8

output:
ds 4

;these libraries allow us to write the output to the screen
read "\SrcCPC\winape_monitor.asm"
read "\SrcCPC\winape_stringop.asm"
read "\SrcCPC\winape_showhex.asm"

square_small:
;returns a*a into a
LD C,B
mul8_small:
	;multiplies two 8-bit regs, product is also 8 bit.
	;no overflow protection!
	;computes A = c * b
	ld a,c
	or a
	ret z
	
	djnz skip_return_C
	;ADVANCED TRICKERY:
	;	we need to decrement B anyway.
	;	also if B = 1, then A = C.
	;	C is already in A, which we need for the multiplication regardless.
	;	This does the job for us in one instruction!
	;	Most DJNZs are backward but this one is FORWARD!
	ret
skip_return_C:
	add C
	djnz skip_return_C
	ret