; Macro: Performs the Invert Mask function on a data selection.
; If no selection is made, it operates on the entire data window.
;
CM       ; Clear all Memory Registers
;
; Storage Locations
; 00 - First column getting masked
; 01 - Last column getting masked
; 02 - Number of rows in data window
; 03 - Column Counter
; 04 - Row Counter
; 06 - Row and Col. # in decimal form 
;
ibase
0e+00
STO 00
size     ; Returns the size of the data window
STO 02   ; Stores the number of rows that are in the data window
down     ; Pushes the stack down to obtain number of columns
1
 -       ; Subtract one from number of columns
STO 01   ; Store number of columns in 01
RCL 00   ; Recall column number
STO 03   ; Set Column Counter
GTO 50   ; Store column in decimal form
;
LBL 10
XEQ 20
RCL 01   ; Recall final column value
ISG 03   ; Increment counter by 1, are contents of 03 <= 01
GTO 50   ; Yes - Increase column
STOP     ; No - Stop program
;
LBL 20
RCLi 06  ; Recall data from cell specified in mem. reg. 06
test 1   ; Test for an empty cell
GTO 25
test 2   ; Test for masked data cell
GTO 35
Mi 06    ; Mask the cell specified in 06
;
LBL 25
0e+00
DSE 04   ; Decrement counter by 1, are contents of 02 > 0.0
GTO 40   ; Yes - Increase row number by 1
RTN
;
LBL 35
UMi 06   ; Unmask the cell specified in 06
GTO 25
;
LBL 40
XEQ 70   ; Increase current address
GTO 20
;
LBL 50
RCL 03   ; Recall current column
1000
 /       ; Divide column by 1000
STO 06   ; Store column in decimal format 
XEQ 60   ; Reset Row Counter
GTO 10
;
LBL 60
RCL 02
STO 04   ; Reset Row Counter
RTN
;
LBL 70
1
ADD 06   ; Increase address by 1
RTN
;
; Version 1.0 - August 30, 2001
; by Steve Wilson