diff --git a/main.asm b/main.asm
index fa05e1c..709d3f7 100644
--- a/main.asm
+++ b/main.asm
@@ -5009,7 +5009,10 @@ NOCLRPAR:
     RET
 
 ; --------------------------------------------------
-; Get parameters X, Y and Color, and check
+; Get parameters X, Y, and check Y<256
+; Out: BC - Y coordinate (0..255)
+;      DE - X coordinate
+;       A - Y coordinate (0..255)
 ; --------------------------------------------------
 GET_XYC_CHK:
     CALL  GET_XYC
@@ -5073,9 +5076,8 @@ PSETMONO:
     LD    A, (HL)
     OR    C
     LD    (HL), A
-    DB    LD_HL_nn
-OPSTPOS:
-    DW    0x0000
+OPSTPOS   EQU $+1
+    LD    HL, 0
     RET
 
 ; --------------------------------------------------
@@ -5112,7 +5114,7 @@ GET_WHC:
     RET
 
 ; --------------------------------------------------
-; BOX [(X, Y)] W, H[, forecolr, bgcolr] statement
+; BOX [(X, Y)] W, H[, forecolor, bgcolor] statement
 ; --------------------------------------------------
 BOX:
     LD    A, (CUR_VMODE)