diff --git a/Makefile b/Makefile
index c94074b..bd14c7d 100644
--- a/Makefile
+++ b/Makefile
@@ -2,11 +2,8 @@
 
 all : mandel.xex
 
-mandel.xex : mandel.o mandel-core.o tables.o atari-xex.cfg
-	ld65 -C ./atari-xex.cfg --mapfile mandel.map -o $@ mandel.o mandel-core.o tables.o atari.lib
-
-mandel.s : mandel.c mandel.h
-	cc65 -o $@ mandel.c
+mandel.xex : mandel.o tables.o atari-asm-xex.cfg
+	ld65 -C ./atari-asm-xex.cfg -o $@ mandel.o tables.o
 
 %.o : %.s
 	ca65 -o $@ $<
@@ -16,7 +13,6 @@ tables.s : tables.js
 
 clean :
 	rm -f tables.s
-	rm -f mandel.s
 	rm -f *.o
 	rm -f *.xex
-	rm -f mandel.map
+
diff --git a/atari-xex.cfg b/atari-xex.cfg
deleted file mode 100644
index 467d9d4..0000000
--- a/atari-xex.cfg
+++ /dev/null
@@ -1,69 +0,0 @@
-# Sample linker configuration for C programs using the Atari binary file support.
-# Use with: cl65 -tatari -Catari-xex.cfg prog.c -o prog.xex
-FEATURES {
-    STARTADDRESS: default = $8000;
-}
-SYMBOLS {
-    __SYSTEM_CHECK__:    type = import;  # force inclusion of "system check" load chunk
-    __STACKSIZE__:       type = weak, value = $0800; # 2k stack
-    __STARTADDRESS__:    type = export, value = %S;
-    __RESERVED_MEMORY__: type = weak, value = $0000;
-    __SYSCHKHDR__:       type = export, value = 0; # Disable system check header
-    __SYSCHKTRL__:       type = export, value = 0; # Disable system check trailer
-    __TABLESEG_START__:    type = weak, value = $2E00 + $0300;
-    __TABLESEG_SIZE__:     type = weak, value = 6 * $100;
-    __BANKSY_START__:  type = weak, value = $4000;
-    __BANKSY_SIZE__:   type = weak, value = $4000;
-    __FRAMEBUFFER_START__: type = weak, value = $A000;
-}
-MEMORY {
-# Note -- $80 and $81 (LOMEM) appear to be reserved in ZP.
-    ZP:         file = "", define = yes, start = $0082, size = $007E;
-# "system check" load chunk
-    SYSCHKCHNK: file = %O,               start = $2E00, size = $0300;
-# Note $a000-$bfff is against the BASIC cartridge, may require booting with OPTION.
-    TABLES:     file = %O, define = yes, start = __TABLESEG_START__, size = __TABLESEG_SIZE__;
-# We reserve $4000-7fff for the bank-switch window.
-# In theory we could keep data and code here that we only use on 48k/64k systems.
-    BANKSWITCH: file = "", define = yes, start = __BANKSY_START__, size = __BANKSY_SIZE__;
-# "main program" load chunk
-    MAIN:       file = %O, define = yes, start = %S, size = __FRAMEBUFFER_START__ - __STACKSIZE__ - __RESERVED_MEMORY__ - %S;
-}
-FILES {
-    %O: format = atari;
-}
-FORMATS {
-    atari: runad = start,
-           initad = SYSCHKCHNK: __SYSTEM_CHECK__;
-}
-SEGMENTS {
-    ZEROPAGE:  load = ZP,         type = zp;
-    EXTZP:     load = ZP,         type = zp,                optional = yes;
-    SYSCHK:    load = SYSCHKCHNK, type = rw,  define = yes, optional = yes;
-    TABLES:    load = TABLES,     type = ro,  optional = yes, align = 256;
-    BANKSWICH: load = BANKSWITCH, type = ro,  optional = yes;
-    STARTUP:   load = MAIN,       type = ro,  define = yes;
-    LOWBSS:    load = MAIN,       type = rw,                optional = yes;  # not zero initialized
-    LOWCODE:   load = MAIN,       type = ro,  define = yes, optional = yes;
-    ONCE:      load = MAIN,       type = ro,                optional = yes;
-    CODE:      load = MAIN,       type = ro,  define = yes;
-    RODATA:    load = MAIN,       type = ro;
-    DATA:      load = MAIN,       type = rw;
-    INIT:      load = MAIN,       type = rw,                optional = yes;
-    BSS:       load = MAIN,       type = bss, define = yes;
-}
-FEATURES {
-    CONDES: type    = constructor,
-            label   = __CONSTRUCTOR_TABLE__,
-            count   = __CONSTRUCTOR_COUNT__,
-            segment = ONCE;
-    CONDES: type    = destructor,
-            label   = __DESTRUCTOR_TABLE__,
-            count   = __DESTRUCTOR_COUNT__,
-            segment = RODATA;
-    CONDES: type    = interruptor,
-            label   = __INTERRUPTOR_TABLE__,
-            count   = __INTERRUPTOR_COUNT__,
-            segment = RODATA,
-            import  = __CALLIRQ__;
-}
diff --git a/mandel.c b/mandel.c
deleted file mode 100644
index f287fa3..0000000
--- a/mandel.c
+++ /dev/null
@@ -1,15 +0,0 @@
-/**
- * The UI and I/O wrapper for the Mandelbrot runner, in C.
- *
- * For the moment *all* logic is in mandel-core.s, I'm just
- * trying to get this to run within a cc65 environment.
- * Eventually just the inner loop fun will live in there.
- */
-
-#include <stdlib.h>
-#include <stdio.h>
-#include "mandel.h"
-
-void main(void) {
-    mandel_start();
-}
\ No newline at end of file
diff --git a/mandel.h b/mandel.h
deleted file mode 100644
index e43fad7..0000000
--- a/mandel.h
+++ /dev/null
@@ -1,4 +0,0 @@
-#include <inttypes.h>
-
-// From mandel-core.s:
-extern void mandel_start(void);
diff --git a/mandel-core.s b/mandel.s
similarity index 93%
rename from mandel-core.s
rename to mandel.s
index 6ebb089..6837e00 100644
--- a/mandel-core.s
+++ b/mandel.s
@@ -126,10 +126,6 @@ KEY_7     = 51
 KEY_8     = 53
 KEY_9     = 48
 KEY_0     = 50
-KEY_PERIOD = 34
-KEY_E     = 42
-KEY_X     = 22
-KEY_Y     = 43
 
 .struct float48
     exponent .byte
@@ -361,7 +357,7 @@ z_buffer:
         .word 0
     .endrepeat
 
-.export _mandel_start
+.export start
 
 ;max_fill_level = 6
 max_fill_level = 3
@@ -407,13 +403,6 @@ elapsed_work:
 elapsed_digit:
     .byte 0
 
-input_col:
-    .byte 0
-input_row:
-    .byte 0
-input_max:
-    .byte 0
-
 ; 2 + 9 * byte cycles
 .macro add bytes, dest, arg1, arg2
     clc ; 2 cyc
@@ -461,7 +450,7 @@ input_max:
     sub 4, dest, arg1, arg2
 .endmacro
 
-; 3 + 5 * (bytes - 1) cycles
+; 3 + 5 * bytes cycles
 .macro shl bytes, arg
     asl arg              ; 3 cyc
     .repeat bytes-1, i
@@ -469,23 +458,22 @@ input_max:
     .endrepeat
 .endmacro
 
-; 8 cycles
+; 13 cycles
 .macro shl16 arg
     shl 2, arg
 .endmacro
 
-; 13 cycles
+; 18 cycles
 .macro shl24 arg
     shl 3, arg
 .endmacro
 
-; 18 cycles
+; 23 cycles
 .macro shl32 arg
     shl 4, arg
 .endmacro
 
 ; 6 * bytes cycles
-; 4 * bytes bytes
 .macro copy bytes, dest, arg
     .repeat bytes, byte ; 6 * bytes cycles
         lda arg + byte  ; 3 cyc
@@ -494,7 +482,6 @@ input_max:
 .endmacro
 
 ; 12 cycles
-; 8 bytes
 .macro copy16 dest, arg
     copy 2, dest, arg
 .endmacro
@@ -529,19 +516,17 @@ input_max:
     neg 4, arg
 .endmacro
 
-; 11-27 + 18 * shift cycles
-; 65-81 cycles for shift=3
+; 11-27 + 23 * shift cycles
+; 103-119 cycles for shift=4
 .macro shift_round_16 arg, shift
     .repeat shift
-        shl32 arg ; 18 cycles
+        shl32 arg ; 23 cycles
     .endrepeat
     round16 arg ; 11-27 cycles
 .endmacro
 
 ; input: arg1, arg2 as fixed4.12
 ; output: dest as fixed8.24
-; patch point jsr at 16 bytes in
-imul16_patch_offset = 16
 .macro imul16 dest, arg1, arg2
     copy16 FR0, arg1  ; 12 cyc
     copy16 FR1, arg2  ; 12 cyc
@@ -551,8 +536,6 @@ imul16_patch_offset = 16
 
 ; input: arg as fixed4.12
 ; output: dest as fixed8.24
-; patch point jsr at 8 bytes in
-sqr16_patch_offset = 8
 .macro sqr16 dest, arg
     copy16 FR0, arg   ; 12 cyc
     jsr sqr16_func    ; ? cyc
@@ -698,6 +681,71 @@ bank_switch_table:
     .endif
 .endmacro
 
+.proc imul8xe_init
+
+    bank_switch 0
+    lda #0
+    sta EXTENDED_RAM
+    bank_switch 1
+    lda #1
+    sta EXTENDED_RAM
+    bank_switch 0
+    lda EXTENDED_RAM
+    beq init
+
+    ; no bank switching available, we just overwrite the value in base ram
+    rts
+
+init:
+
+    ; patch imul16_func into a forwarding thunk to imul16xe_func
+    lda #$4c ; 'jmp' opcode
+    sta imul16_func
+    lda #.lobyte(imul16xe_func)
+    sta imul16_func + 1
+    lda #.hibyte(imul16xe_func)
+    sta imul16_func + 2
+
+    ; ditto for sqr16_func -> sqr16xe_func
+    lda #$4c ; 'jmp' opcode
+    sta sqr16_func
+    lda #.lobyte(sqr16xe_func)
+    sta sqr16_func + 1
+    lda #.hibyte(sqr16xe_func)
+    sta sqr16_func + 2
+
+    ; create the lookup table
+    ; go through the input set, in four 16KB chunks
+
+    arg1 = FR1
+    arg2 = FR2
+    result = FR0
+
+    lda #$00
+    sta arg1
+    sta arg2
+    sta ptr
+    lda #$40
+    sta ptr + 1
+
+    ; $00 * $00 -> $3f * $ff
+    bank_switch 0
+    jsr imul8xe_init_section
+
+    ; $40 * $00 -> $7f * $ff
+    bank_switch 1
+    jsr imul8xe_init_section
+
+    ; $80 * $00 -> $bf * $ff
+    bank_switch 2
+    jsr imul8xe_init_section
+
+    ; $c0 * $00 -> $ff * $ff
+    bank_switch 3
+    jsr imul8xe_init_section
+
+    rts
+.endproc
 
 ; Initialize a 16 KB chunk of the table
 ; input: multipliers in temp
@@ -935,17 +983,6 @@ common:
 
 .endproc
 
-; rounds to 16-bit first!
-; input in FR0, 32 bits signed 6.26 fixed
-; output in FR0, Atari float
-; clobbers a, x, y, FR0, FR1
-.proc fixed6_26_to_float
-    shift_round_16 FR0, 3
-    copy16 FR0, FR0 + 2
-    jsr fixed3_13_to_float
-    rts
-.endproc
-
 ; input in FR0, Atari float
 ; output in FR0, 16 bits signed 3.13 fixed
 ; clobbers a, x, y, FR0, FR1
@@ -1097,15 +1134,12 @@ keep_going:
     shift_round_16 zy, 3
 
     ; zx_2 = zx * zx
-fixup_sqr16_1:
     sqr16 zx_2, zx + 2
 
     ; zy_2 = zy * zy
-fixup_sqr16_2:
     sqr16 zy_2, zy + 2
 
     ; zx_zy = zx * zy
-fixup_imul16_1:
     imul16 zx_zy, zx + 2, zy + 2
 
     ; dist = zx_2 + zy_2
@@ -1569,7 +1603,7 @@ number_keys:
     beq five
     cpy #KEY_6
     beq six
-    jmp letter_keys
+    jmp skip_char
 
 one:
     ldx #0
@@ -1588,21 +1622,7 @@ five:
     jmp load_key_viewport
 six:
     ldx #5
-    jmp load_key_viewport
-
-letter_keys:
-    cpy #KEY_X
-    bne not_x
-    jsr input_x
-    jmp done
-not_x:
-    cpy #KEY_Y
-    bne not_y
-    jsr input_y
-    jmp done
-not_y:
-    jmp skip_char
-
+    ; fall through
 load_key_viewport:
     jsr load_viewport
     ; fall through
@@ -1612,23 +1632,6 @@ done:
 
 .endproc
 
-.proc input_x
-    ldx #col_x
-    ldy #1
-    jsr input_number
-
-
-    rts
-.endproc
-
-.proc input_y
-    rts
-.endproc
-
-.proc input_number
-    rts
-.endproc
-
 .proc clear_screen
     ; zero the range from framebuffer_top to display_list
     lda #.lobyte(framebuffer_top)
@@ -1676,7 +1679,9 @@ zero_byte_loop:
     draw_string_const str_x
 
     copy32 FR0, ox
-    jsr fixed6_26_to_float
+    shift_round_16 FR0, 3
+    copy16 FR0, FR0 + 2
+    jsr fixed3_13_to_float
     jsr FASC
     jsr draw_string
 
@@ -1685,7 +1690,9 @@ zero_byte_loop:
     draw_string_const str_y
 
     copy32 FR0, oy
-    jsr fixed6_26_to_float
+    shift_round_16 FR0, 3
+    copy16 FR0, FR0 + 2
+    jsr fixed3_13_to_float
     jsr FASC
     jsr draw_string
 
@@ -1745,7 +1752,7 @@ zero_byte_loop:
     rts
 .endproc
 
-.proc _mandel_start
+.proc start
 
     jsr imul8xe_init
 
@@ -1984,25 +1991,51 @@ update_status:
     lda FR0 + 1
     sta elapsed_work + 1
 
-    draw_string_const str_space
-    
-    .macro do_countdown divisor, digits
-        ldx #.lobyte(divisor)
-        ldy #.hibyte(divisor)
-        lda #.lobyte(digits)
-        sta INBUFF
-        lda #.hibyte(digits)
-        sta INBUFF + 1
-        jsr countdown
+    ;jsr IFP
+    ;jsr FASC
+    ;jsr draw_string
+
+    .macro countdown divisor, digits
+        .scope
+            ; count the hours
+            ldx #0
+        countdown_loop:
+            lda elapsed_work + 1
+            cmp #.hibyte(divisor)
+            bcc countdown_done
+            lda elapsed_work
+            cmp #.lobyte(divisor)
+            bcc countdown_done
+            sec
+            lda elapsed_work
+            sbc #.lobyte(divisor)
+            sta elapsed_work
+            lda elapsed_work + 1
+            sbc #.hibyte(divisor)
+            sta elapsed_work + 1
+            inx
+            jmp countdown_loop
+        countdown_done:
+            lda digits,x
+            eor #$80
+            sta elapsed_digit
+            lda #.lobyte(elapsed_digit)
+            sta INBUFF
+            lda #.hibyte(elapsed_digit)
+            sta INBUFF + 1
+            jsr draw_string
+        .endscope
     .endmacro
-    do_countdown 36000, digits_space
-    do_countdown 3600, digits_zero
+
+    draw_string_const str_space
+    countdown 36000, digits_space
+    countdown 3600, digits_zero
     draw_string_const str_h
-    do_countdown 600, digits_zero
-    do_countdown 60, digits_zero
+    countdown 600, digits_zero
+    countdown 60, digits_zero
     draw_string_const str_m
-    do_countdown 10, digits_zero
-    do_countdown 1, digits_zero
+    countdown 10, digits_zero
+    countdown 1, digits_zero
     draw_string_const str_s
 
 skipped:
@@ -2064,118 +2097,3 @@ loop:
     jmp main_loop
 
 .endproc
-
-; digit string in INBUFF
-; divisor X/Y
-; clobbers temp, calls draw_string
-.proc countdown
-    divisor = temp
-    stx divisor
-    sty divisor + 1
-
-    ; count the hours
-    ldy #0
-countdown_loop:
-    lda elapsed_work + 1
-    cmp divisor + 1
-    beq countdown_lobyte
-    bcc countdown_done
-    bcs countdown_inc
-countdown_lobyte:
-    lda elapsed_work
-    cmp divisor
-    bcc countdown_done
-countdown_inc:
-    sec
-    lda elapsed_work
-    sbc divisor
-    sta elapsed_work
-    lda elapsed_work + 1
-    sbc divisor + 1
-    sta elapsed_work + 1
-    iny
-    jmp countdown_loop
-countdown_done:
-    lda (INBUFF),y
-    eor #$80
-    sta elapsed_digit
-    lda #.lobyte(elapsed_digit)
-    sta INBUFF
-    lda #.hibyte(elapsed_digit)
-    sta INBUFF + 1
-    jsr draw_string
-    rts
-.endproc
-
-.proc imul8xe_init
-
-    bank_switch 0
-    lda #0
-    sta EXTENDED_RAM
-    bank_switch 1
-    lda #1
-    sta EXTENDED_RAM
-    bank_switch 0
-    lda EXTENDED_RAM
-    beq init
-
-    ; no bank switching available, we just overwrite the value in base ram
-    rts
-
-init:
-
-    ; patch imul16_func into a forwarding thunk to imul16xe_func
-    lda #$4c ; 'jmp' opcode
-    sta imul16_func
-    lda #.lobyte(imul16xe_func)
-    sta imul16_func + 1
-    sta mandelbrot::fixup_imul16_1 + imul16_patch_offset + 1
-    lda #.hibyte(imul16xe_func)
-    sta imul16_func + 2
-    sta mandelbrot::fixup_imul16_1 + imul16_patch_offset + 2
-
-    ; ditto for sqr16_func -> sqr16xe_func
-    lda #$4c ; 'jmp' opcode
-    sta sqr16_func
-    lda #.lobyte(sqr16xe_func)
-    sta sqr16_func + 1
-    sta mandelbrot::fixup_sqr16_1 + sqr16_patch_offset + 1
-    sta mandelbrot::fixup_sqr16_2 + sqr16_patch_offset + 1
-    lda #.hibyte(sqr16xe_func)
-    sta sqr16_func + 2
-    sta mandelbrot::fixup_sqr16_1 + sqr16_patch_offset + 2
-    sta mandelbrot::fixup_sqr16_2 + sqr16_patch_offset + 2
-
-
-    ; create the lookup table
-    ; go through the input set, in four 16KB chunks
-
-    arg1 = FR1
-    arg2 = FR2
-    result = FR0
-
-    lda #$00
-    sta arg1
-    sta arg2
-    sta ptr
-    lda #$40
-    sta ptr + 1
-
-    ; $00 * $00 -> $3f * $ff
-    bank_switch 0
-    jsr imul8xe_init_section
-
-    ; $40 * $00 -> $7f * $ff
-    bank_switch 1
-    jsr imul8xe_init_section
-
-    ; $80 * $00 -> $bf * $ff
-    bank_switch 2
-    jsr imul8xe_init_section
-
-    ; $c0 * $00 -> $ff * $ff
-    bank_switch 3
-    jsr imul8xe_init_section
-
-    rts
-.endproc