update cursor save/cursor restore to also save the DECOM settings. tested with vt100 (mame)

vt.equ.S

@@ -82,6 +82,7 @@ mod		ds 2
 * saved cursor
 saved_x	ds 2
 saved_y	ds 2
+saved_decom ds 2
 
 	do *>256
 	err "too big"

vt100.esc.S

@@ -134,21 +134,24 @@ vt100_esc ent
 
 
 esc_7 ; save cursor position, graphic rendition, and character set.
-
+* based on testing, DECOM is also saved/restored.
 	lda x
 	sta saved_x
 	lda y
 	sta saved_y
+	lda DECOM
+	sta saved_decom
 
 	rts
 esc_8 ; restore cursor position, graphic rendition, and character set.
 
-* TODO - how does this interact with DECOM?
-
 	lda saved_x
 	sta x
 	lda saved_y
 	sta y
+	lda saved_decom
+	sta DECOM
+
 	jmp recalc_cursor
 
 esc_eq ; enter alternate keypad mode