Updated the cx16 library to the Commander X16's ROM prerelease 37.

libsrc/cx16/cpeekrevers.s

@@ -1,6 +1,6 @@
 ;
 ; 2016-02-28, Groepaz
-; 2019-09-25, Greg King
+; 2020-04-30, Greg King
 ;
 ; unsigned char cpeekrevers (void);
 ; /* Return the reverse attribute from the current cursor position.
@@ -15,8 +15,15 @@
 
 _cpeekrevers:
         php
+        lda     CURS_FLAG       ; is the cursor currently off?
+        bne     @L1
         sei                     ; don't let cursor blinking interfere
-        stz     VERA::CTRL      ; use port 0
+        ldx     CURS_STATE      ; is cursor currently displayed?
+        beq     @L1             ; jump if not
+        lda     CURS_CHAR       ; get screen code under cursor
+        bra     @L2
+
+@L1:    stz     VERA::CTRL      ; use port 0
         lda     CURS_Y
         sta     VERA::ADDR+1    ; set row number
         stz     VERA::ADDR+2
@@ -24,7 +31,7 @@ _cpeekrevers:
         asl     a               ; each character has two bytes
         sta     VERA::ADDR
         lda     VERA::DATA0     ; get screen code
-        plp
+@L2:    plp
         and     #%10000000      ; get reverse bit
         asl     a
         tax                     ; ldx #>$0000