git.sur5r.net Git - cc65/blob - libsrc/cbm510/systime.s

   1 ;
   2 ; Stefan Haubenthal, 2009-07-27
   3 ; Ullrich von Bassewitz, 2009-09-24
   4 ;
   5 ; time_t _systime (void);
   6 ; /* Similar to time(), but:
   7 ; **   - Is not ISO C
   8 ; **   - Does not take the additional pointer
   9 ; **   - Does not set errno when returning -1
  10 ; */
  11 ;
  12
  13         .include        "time.inc"
  14         .include        "cbm510.inc"
  15         .include        "extzp.inc"
  16
  17         .import         sys_bank, restore_bank
  18         .importzp       tmp1, tmp2
  19
  20
  21 ;----------------------------------------------------------------------------
  22 .code
  23
  24 .proc   __systime
  25
  26 ; Switch to the system bank
  27
  28         jsr     sys_bank
  29
  30 ; Read the clock
  31
  32         ldy     #CIA::TODHR
  33         lda     (cia2),y
  34         bpl     AM
  35         and     #%01111111
  36         sed
  37         clc
  38         adc     #$12
  39         cld
  40 AM:     jsr     BCD2dec
  41         sta     TM + tm::tm_hour
  42         ldy     #CIA::TODMIN
  43         lda     (cia2),y
  44         jsr     BCD2dec
  45         sta     TM + tm::tm_min
  46         ldy     #CIA::TODSEC
  47         lda     (cia2),y
  48         jsr     BCD2dec
  49         sta     TM + tm::tm_sec
  50         ldy     #CIA::TOD10
  51         lda     (cia2),y                ; Dummy read to unfreeze
  52
  53 ; Restore the bank
  54
  55         jsr     restore_bank
  56
  57 ; Convert to a time
  58
  59         lda     #<TM
  60         ldx     #>TM
  61         jmp     _mktime
  62
  63 .endproc
  64
  65 ;----------------------------------------------------------------------------
  66 ; dec = (((BCD>>4)*10) + (BCD&0xf))
  67
  68 .proc   BCD2dec
  69
  70         tax
  71         and     #%00001111
  72         sta     tmp1
  73         txa
  74         and     #%11110000      ; *16
  75         lsr                     ; *8
  76         sta     tmp2
  77         lsr
  78         lsr                     ; *2
  79         adc     tmp2            ; = *10
  80         adc     tmp1
  81         rts
  82
  83 .endproc
  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