Table of Contents
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A list of small routines that can help you. Feel free to add your own.
Battery Status
Directly polls the hardware for battery status. Thanks to Steve Riekeberg.
;Name: BatteryStatus
;Description: Returns if the batteries are good, or low and need changing.
;Inputs: None
;Outputs: Non-Zero = Good Batteries
Zero = Batteries Low
;Destroys: A
GetBatteryStatus:
in a, (2)
and 01h
ret
Boundary Check
Checks if coordinates is inside a designated box. Thanks to Adm. Wiggin.
; Your box coords (will not work with 0, keep x1 < x2, and y1 < y2 [duh])
#define x1 10
#define y1 10
#define x2 20
#define y2 30
check:
; a = x
; b = y
; returns c flag set if good
; returns c flag reset if no good (nc)
; destorys af (quite obvious if one knows any z80 at all)
cp x1
jr c,nogood
cp x2+1
jr nc,nogood
ld a,b
cp y1
jr c,nogood
cp y2+1
jr nc,nogood
;if it gets here, it's in the box! Yay! Hooray! Peoples rejoice!
; as a side effect of the last operation, the carry flag is already set.
ret
nogood:
or a;to reset the carry flag
ret
Center Text
Displays a string centered on the screen (small font). Thanks to WikiGuru.
;input:hl points to string
;output: string displayed centered on screen
;destroyed: all registers
;other remarks: (penrow) must be set before calling this sub-routine
; first byte of string must be the length of the string
centertxt:
bcall(_SStringLength)
ld a,96 ;width of screen
sub b ;subtract width of string
rra ;divide by 2 to be centered
ld (pencol),a
ld b,(hl)
inc hl
bcall(_VPutSN)
ret
;to call:
...
ld hl,0
ld (penrow),hl
ld hl,txtTest
call centertxt
...
txtTest:
.db 11,"Sample Text"
Direct Input
Used for direct input. See here to learn more about direct input. Thanks to Steve Riekeberg.
;Name: DirectInput
;Inputs: A = Key Group
;Outputs: A = Key Code; Zero If None
;Destroys: A, B
DirectInput:
ld b,a
ld a,$ff ;Reset the keypad
out (1),a
ld a,b
out (1),a
in a,(1)
ret
Hotspot
Checks if h>b, l>c, h<d, and l<e. Thanks to kermmartian and DarkerLine.
;----------Hot spot detection-----------
;inputs: b,c (first x and y cor)
; d,e (last x and y cor)
; h,l (current x,y)
;output: "c" flag [either true (set) or false (reset)]
hdetect:
ld a,h
cp b
ccf
ret nc
cp d
ret nc
ld a,l
cp c
ccf
ret nc
cp e
ret
On/Off Calc
Turns the calculator "off" and waits for user to press on. Note: Pulling batteries out will result in Ram Clear. Thanks to Taricorp.
;no inputs
ld a,02h
out (10h),a ;Turn off LCD
ld a,08h
out (3),a
call LCD_Delay
ld a,36h
out (4),a
ld a,01h
out (3),a
halt ;It halts until ON is pressed
ld a,0Bh
out (3),a
ld a,03h
out (10h),a ;Turn the LCD back on
res onKey,(iy+keyFlags)
Find Next App
This routine is useful if you want to manually search through the installed apps on a calculator.
FindNextApp:
;Inputs:
; B is the base page of the app.
;Outputs:
; c flag set if the field was found
; nc means the app header subfield was not found
; B is the number of pages of the app
; A is the page of the next app
; H is the input page number
; L is the page number of the currently swapped in page in bank 1
;
;Comments:
; This code must run in RAM
in a,(6)
ld c,a
push bc ;b is the app page, c is the current page
ld a,b
out (6),a
call FindNumPages
pop hl ;h is the app page, l is the current page
ld b,a
ld a,l
out (6),a
ld a,h
ret nc
sub b
scf
ret
FindNumPages:
;Outputs:
; c flag set if the field was found
; nc means the app header subfield was not found
; A is the number of app pages
; B is 0
; (HL) is the number of app pages
ld hl,4000h
ld bc,128
ld a,c
or a
FNPLoop:
cpir
ret po
ret nz
inc a
cp (hl)
jr z,$+6
dec a
jp FNPLoop
inc l
ld a,(hl)
scf
ret
IncHLMem1
When reading through data in MemBank1, this routine is particularly useful as it adjusts the flash pages accordingly, as well as the pointer HL. If HL does not point to data in MemBank1 (4000h~7FFFh) then HL will simply be incremented, which is useful if the data might be in RAM or flash.
IncHLMem1:
inc l ; 4 4*16384 65536
ret nz ;11| 5 64*5+16320*11 179840
inc h ; 4 4*64 256
ret po ;11| 5 11*63+5 698
ld h,a
in a,(6) ; 11 11 11
inc a ; 4 4 4
out (6),a ; 11 11 11
ld a,h
ld h,40h ; 7 7 7
ret ; 10 10
It destroys no registers and is very efficient. However, if you are really in need of speed, such as with a ReadArc routine, you can try something like this (conditionally calling the routine):
inc l
call z,IncMem1Ptr
<<rest of code>>
IncMem1ptr
inc h ; 4 4*64 256
ret po ;11| 5 11*63+5 698
ld h,a
in a,(6) ; 11 11 11
inc a ; 4 4 4
out (6),a ; 11 11 11
ld a,h
ld h,40h ; 7 7 7
ret ; 10 10
SortA
This code is not as efficient as it could be, but it works. it sorts a bunch of bytes to be in ascending order:
SortA:
;Inputs:
; BC is the size
; HL is where the data is located
;Takes at least n iterations, at most n(n+1)/2
ld d,h
ld e,l
SortALoop:
push bc
push de
ld a,(hl)
call SwapBytes
SortLoop1:
jp po,NextSort
cp (hl)
cpi
jr c,SortLoop1
dec hl
call z,SwapBytes
jr c,SortLoop1
EndSwap:
pop de
jr SortALoop+1
NextSort:
pop hl
pop bc
dec hl
add hl,bc
or a
sbc hl,de
ret c
ret z
ld b,h
ld c,l
inc bc
ex de,hl
jp SortA+1
SwapBytes:
inc bc
push af
ld a,(de)
ldi
dec hl
ld (hl),a
inc hl
pop af
scf
ret
Set15MHz
This routine will set the calculator to 15MHz mode if possible:
Set15MHz:
;Ouputs:
; Sets the calculator to 15MHz if possible
; z flag set if the calc is at 6MHz, nz if at 15MHz
in a,(2)
rlca
and 1
out (20h),a
ret
Set6MHz
This is pretty tiny (3 bytes) so it isn't worth making it a subroutine. In other words, just use it inline:
xor a
out (20h),a