Heres a code snippet, that might be useful:

; ANSI / VT100 Cursor positioning (Row ; Col) in 6502 assembler
; CURX is the memory location for the X position, and
; CURY the one for the Y position...
; TEMP is somewhere...
; CHOUT on the KIM-1 is $1EA0

GOTOXY:
LDA #$1B ; ESC
JSR CHOUT
LDA #$5B ...