diff --git a/.travis.yml b/.travis.yml
index 7ed60b4..2eed917 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,8 +8,11 @@ compiler:
 script:
     - cmake . -DCMAKE_BUILD_TYPE=Release
     - make
-    - ./l65 samples/vcs0.l65
-    - ./l65 samples/vcs1.l65
+    - cd samples
+    - ../l65 vcs0.l65
+    - ../l65 vcs1.l65
+    - ../l65 vcs_hello.l65
+    - cd ..
 deploy:
     provider: releases
     api_key:
diff --git a/6502.lua b/6502.lua
index cf96fa2..a7a7a75 100644
--- a/6502.lua
+++ b/6502.lua
@@ -628,8 +628,8 @@ M.charset = function(s, f)
     if st == 'table' then M.cs = s return s end
     if not f then f = function(v) return v end
     elseif type(f) == 'number' then f = function(v) return v + f end end
-    local t={}
-    for c in s:gmatch'.' do t[c]=f(#t) end
+    local t,i={},0
+    for c in s:gmatch'.' do t[c]=f(i) i=i+1 end
     M.cs=t
     return t
 end
diff --git a/samples/vcs_hello.l65 b/samples/vcs_hello.l65
new file mode 100644
index 0000000..4eff762
--- /dev/null
+++ b/samples/vcs_hello.l65
@@ -0,0 +1,91 @@
+require'vcs'
+mappers['2K']()
+
+local tmp = 0x80
+
+section{ "font", align=256 } dc.b
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,-- <SPC>
+    0x18,0x3c,0x66,0x7e,0x66,0x66,0x66,0x00,-- A
+    0x7c,0x66,0x66,0x7c,0x66,0x66,0x7c,0x00,-- B
+    0x3c,0x66,0x60,0x60,0x60,0x66,0x3c,0x00,-- C
+    0x78,0x6c,0x66,0x66,0x66,0x6c,0x78,0x00,-- D
+    0x7e,0x60,0x60,0x78,0x60,0x60,0x7e,0x00,-- E
+    0x7e,0x60,0x60,0x78,0x60,0x60,0x60,0x00,-- F
+    0x3c,0x66,0x60,0x6e,0x66,0x66,0x3c,0x00,-- G
+    0x66,0x66,0x66,0x7e,0x66,0x66,0x66,0x00,-- H
+    0x3c,0x18,0x18,0x18,0x18,0x18,0x3c,0x00,-- I
+    0x1e,0x0c,0x0c,0x0c,0x0c,0x6c,0x38,0x00,-- J
+    0x66,0x6c,0x78,0x70,0x78,0x6c,0x66,0x00,-- K
+    0x60,0x60,0x60,0x60,0x60,0x60,0x7e,0x00,-- L
+    0x63,0x77,0x7f,0x6b,0x63,0x63,0x63,0x00,-- M
+    0x66,0x76,0x7e,0x7e,0x6e,0x66,0x66,0x00,-- N
+    0x3c,0x66,0x66,0x66,0x66,0x66,0x3c,0x00,-- O
+    0x7c,0x66,0x66,0x7c,0x60,0x60,0x60,0x00,-- P
+    0x3c,0x66,0x66,0x66,0x66,0x3c,0x0e,0x00,-- Q
+    0x7c,0x66,0x66,0x7c,0x78,0x6c,0x66,0x00,-- R
+    0x3c,0x66,0x60,0x3c,0x06,0x66,0x3c,0x00,-- S
+    0x7e,0x18,0x18,0x18,0x18,0x18,0x18,0x00,-- T
+    0x66,0x66,0x66,0x66,0x66,0x66,0x3c,0x00,-- U
+    0x66,0x66,0x66,0x66,0x66,0x3c,0x18,0x00,-- V
+    0x63,0x63,0x63,0x6b,0x7f,0x77,0x63,0x00,-- W
+    0x66,0x66,0x3c,0x18,0x3c,0x66,0x66,0x00,-- X
+    0x66,0x66,0x66,0x3c,0x18,0x18,0x18,0x00,-- Y
+    0x7e,0x06,0x0c,0x18,0x30,0x60,0x7e,0x00 -- Z
+
+charset(" abcdefghijklmnopqrstuvwxyz", \x(x*8))
+@@text_hello dc.b "hello world"
+
+local print_txt = tmp+1 -- text pointer, can cross
+local print_line_count=tmp -- number of lines to print
+local print_ptr = tmp+3 -- array of pointers to the characters
+-- a = line count
+@@print12
+    sta print_line_count
+    lda#6 sta NUSIZ0 sta NUSIZ1
+    -- set MSB of font character addresses
+    lda#font>>8 ldx#23 @_loadfont sta print_ptr,x dex dex bpl _loadfont
+    -- position sprites
+    samepage
+        sta WSYNC
+        ldx#6 @_delay dex bne _delay
+        sta RESP0 nop sta RESP1 lda#0x70 sta HMP0 lda#0x60 sta HMP1 sta WSYNC sta HMOVE
+    end
+    @_loop
+        -- load text line
+        ldx#0 ldy#0 @_loadline lda (print_txt),y sta print_ptr,x inx inx iny cpy#12 bne _loadline
+        lda#0x80 sta HMP0 sta HMP1
+        ldy#0 samepage @_printline
+            sta WSYNC sta HMOVE
+            -- first scanline
+            lda (print_ptr+2),y sta GRP0 lda (print_ptr+6),y sta GRP1
+            lda (print_ptr+22),y tax sleep(6)
+            lda (print_ptr+10),y sta GRP0 lda (print_ptr+14),y sta GRP1 lda (print_ptr+18),y sta GRP0 stx GRP1
+            sta HMCLR sleep(8) sta HMOVE
+            -- second scanline
+            lda (print_ptr),y sta GRP0 lda (print_ptr+4),y sta GRP1
+            lda (print_ptr+20),y tax lda#0x80 sta HMP0 sta HMP1 nop
+            lda (print_ptr+8),y sta GRP0 lda (print_ptr+12),y sta GRP1 lda (print_ptr+16),y sta GRP0 stx GRP1
+            iny cpy#8 bne _printline
+        end
+        dec print_line_count beq _end
+        lda print_txt clc adc#12 sta print_txt lda print_txt+1 adc#0 sta print_txt+1
+    jmp _loop
+@_end
+    lda#0 sta GRP0 sta GRP1
+    rts
+
+local kernel = function()
+    ldx#40 @_blank sta WSYNC dex bne _blank
+    setptr(text_hello,print_txt) lda#1 jsr print12
+end
+
+@@main
+    init()
+    lda#0xaa sta COLUP0 sta COLUP1
+@_frame
+    overscan() vblank() screen(kernel) jmp _frame
+
+;
+writebin(filename..'.bin')
+writesym(filename..'.sym')
+print(stats)
diff --git a/vcs.l65 b/vcs.l65
index 82ae5f0..caedee6 100644
--- a/vcs.l65
+++ b/vcs.l65
@@ -182,8 +182,8 @@ screen_begin = function() lda#TV.TIM_KERNEL sta T1024T end
 screen_end = wait
 screen = function(f) screen_begin() if f then f() end screen_end() end
 
-setptr = function(f) lda#op_resolve(f)&0xff sta mappers.tmp lda#op_resolve(f)>>8 sta mappers.tmp+1 end
-xcall = function(f) setptr(f) jsr jmpfar end
+setptr = function(f, add) if not add then add=tmp end lda#op_resolve(f)&0xff sta add lda#op_resolve(f)>>8 sta add+1 end
+xcall = function(f) setptr(f, mappers.tmp) jsr jmpfar end
 rtximp = function() jmp rtsfar end
 
 -- for mappers that swap banks in place