git.sur5r.net Git - cc65/blob - libsrc/c64/systime.s

   1 ;
   2 ; Stefan Haubenthal, 27.7.2009
   3 ;
   4 ; time_t _systime (void);
   5 ; /* Similar to time(), but:
   6 ;  *   - Is not ISO C
   7 ;  *   - Does not take the additional pointer
   8 ;  *   - Does not set errno when returning -1
   9 ;  */
  10 ;
  11
  12         .include        "time.inc"
  13         .include        "c64.inc"
  14         .include        "get_tv.inc"
  15
  16         .constructor    initsystime
  17         .importzp       tmp1, tmp2
  18         .import         _get_tv, _get_ostype
  19
  20
  21 ;----------------------------------------------------------------------------
  22 .code
  23
  24 .proc   __systime
  25
  26         lda     CIA1_TODHR
  27         bpl     AM
  28         and     #%01111111
  29         sed
  30         clc
  31         adc     #$12
  32         cld
  33 AM:     jsr     BCD2dec
  34         sta     TM + tm::tm_hour
  35         lda     CIA1_TODMIN
  36         jsr     BCD2dec
  37         sta     TM + tm::tm_min
  38         lda     CIA1_TODSEC
  39         jsr     BCD2dec
  40         sta     TM + tm::tm_sec
  41         lda     CIA1_TOD10              ; Dummy read to unfreeze
  42         lda     #<TM
  43         ldx     #>TM
  44         jmp     _mktime
  45
  46 ; dec = (((BCD>>4)*10) + (BCD&0xf))
  47 BCD2dec:tax
  48         and     #%00001111
  49         sta     tmp1
  50         txa
  51         and     #%11110000      ; *16
  52         lsr                     ; *8
  53         sta     tmp2
  54         lsr
  55         lsr                     ; *2
  56         adc     tmp2            ; = *10
  57         adc     tmp1
  58         rts
  59
  60 .endproc
  61
  62 ;----------------------------------------------------------------------------
  63 ; Constructor that writes to the 1/10 sec register of the TOD to kick it
  64 ; into action. If this is not done, the clock hangs. We will read the register
  65 ; and write it again, ignoring a possible change in between.
  66
  67 .proc   initsystime
  68
  69         lda     CIA1_TOD10
  70         sta     CIA1_TOD10
  71         jsr     _get_tv
  72         cmp     #TV::PAL
  73         bne     @60Hz
  74         jsr     _get_ostype
  75         cmp     #$43
  76         beq     @60Hz
  77         lda     CIA1_CRA
  78         ora     #$80
  79         sta     CIA1_CRA
  80 @60Hz:  rts
  81
  82 .endproc
  83
  84
  85 ;----------------------------------------------------------------------------
  86 ; TM struct with date set to 1970-01-01
  87 .data
  88
  89 TM:     .word           0       ; tm_sec
  90         .word           0       ; tm_min
  91         .word           0       ; tm_hour
  92         .word           1       ; tm_mday
  93         .word           0       ; tm_mon
  94         .word           70      ; tm_year
  95         .word           0       ; tm_wday
  96         .word           0       ; tm_yday
  97         .word           0       ; tm_isdst
  98