; constants
SPACE_FOR_GOSUB       := $3E
STACK_TOP             := $FA
WIDTH                 := 80 ; Default terminal width
WIDTH2                := 70 ; mac column for zoned print
RAMSTART2             := $0400

; io registers
IO_SCREEN             := $BC00
IO_KBD                := $BC01
IO_ROM_BANKED_OUT     := $BC02
IO_FILE_COMMAND       := $BC03
IO_FILE_DESCRIPTOR    := $BC04
IO_FILE_DATA          := $BC05
IO_FILE_STATUS        := $BC07

; io commands
IO_COMMAND_OPEN       := 1
IO_COMMAND_CLOSE      := 2
IO_COMMAND_SELECT_IN  := 3
IO_COMMAND_SELECT_OUT := 4
IO_COMMAND_READ       := 5
IO_COMMAND_WRITE      := 6
IO_COMMAND_RESET      := 7

; io status
FILE_STATUS_ERROR     := $01
FILE_STATUS_EOF       := $02
FILE_STATUS_READY     := $04

BYTES_FP              := 5
BYTES_PER_ELEMENT     := BYTES_FP
BYTES_PER_VARIABLE    := BYTES_FP+2
MANTISSA_BYTES        := BYTES_FP-1
BYTES_PER_FRAME       := 2*BYTES_FP+8
FOR_STACK1            := 2*BYTES_FP+5
FOR_STACK2            := BYTES_FP+4

STACK                 := $0100
STACK2                := STACK


MAX_EXPON = 10
CR = 13
LF = 10