From: Alan Cox <alan@linux.intel.com>
Date: Sun, 7 Oct 2018 21:58:26 +0000 (+0100)
Subject: ds1302_discard: blow away the now redundant boot time clock setting
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=0e210bc21ebbd008bbf2a8885d16de199e11d8d5;p=FUZIX.git

ds1302_discard: blow away the now redundant boot time clock setting

This is now done nicely in user space
---

diff --git a/Kernel/dev/ds1302_discard.c b/Kernel/dev/ds1302_discard.c
index b26a6cfe..7f520296 100644
--- a/Kernel/dev/ds1302_discard.c
+++ b/Kernel/dev/ds1302_discard.c
@@ -17,56 +17,6 @@
 /* each source file.                                                        */
 /****************************************************************************/
 
-/* we avoid using 32x32 bit multiply ds1302_read_rtc, because it causes sdcc to pull 
-   in a huge __mullong helper -- which is nearly 500 bytes! */
-static uint32_t multiply_8x32(uint8_t a, uint32_t b) __naked /* return a * b */
-{
-    __asm
-        ; WRS -- simple 8x32 multiply routine
-        ; low 16 bits in main registers, high 16 bits in alternate registers
-        ; DE contains b, shifts left, HL contains accumulated result, A contains a, shifts right.
-        ld iy, #0       ; load parameters from stack
-        add iy, sp
-        ld a, 2(iy)     ; load a
-        ld e, 3(iy)     ; load low 16 bits of b
-        ld d, 4(iy)
-        and a           ; clear carry flag
-        sbc hl, hl      ; low result = 0
-        exx
-        sbc hl, hl      ; high result = 0
-        ld e, 5(iy)     ; load high 16 bits of b
-        ld d, 6(iy)
-        exx
-mulgo:                  ; loop executes at most 8 times (depends on highest bit set in a)
-        or a            ; test value of A
-        jr z, muldone   ; if A is now zero we are done
-        rra             ; shift A right one bit, rotate low bit into carry flag
-        jr nc, mulnext  ; if low bit was zero, skip the accumulate
-        add hl, de      ; add low 16 bits
-        exx
-        adc hl, de      ; add high 16 bits
-        exx
-mulnext:
-        and a           ; clear carry flag
-        rl e            ; double low 16 bits
-        rl d
-        exx
-        rl e            ; double high 16 bits
-        rl d
-        exx
-        jr mulgo        ; go again
-muldone:
-        exx             ; get the high 16 bits into DE
-        push hl
-        exx
-        pop de
-        ret             ; return with 32-bit result in DEHL, as per sdcc callng convention
-    __endasm;
-    a; b;  /* squelch compiler warning */
-}
-
-static const uint16_t mktime_moffset[12] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
-
 void ds1302_write_register(uint8_t reg, uint8_t val)
 {
     ds1302_set_pin_ce(true);
@@ -85,69 +35,16 @@ void ds1302_write_seconds(uint8_t seconds)
     irqrestore(irq);
 }
 
-uint32_t ds1302_read_rtc(void)
+void ds1302_check_rtc(void)
 {
-    uint32_t ret;
     uint8_t buffer[7];
-    uint8_t year, month, day, hour, minute, second;
 
     ds1302_read_clock(buffer, 7); /* read all calendar data */
 
-    year   = uint8_from_bcd(buffer[6]);
-    month  = uint8_from_bcd(buffer[4] & 0x1F);
-    day    = uint8_from_bcd(buffer[3] & 0x3F);
-    if(buffer[2] & 0x80) /* AM/PM 12-hour mode */
-        hour   = uint8_from_bcd(buffer[2] & 0x1F) + (buffer[2] & 0x20 ? 12 : 0);
-    else /* sensible 24-hour mode */
-        hour   = uint8_from_bcd(buffer[2] & 0x3F);
-    minute = uint8_from_bcd(buffer[1]);
-    second = uint8_from_bcd(buffer[0] & 0x7F);
-
     if(buffer[0] & 0x80){ /* is the clock halted? */
         kputs("ds1302: start clock\n");
-        ds1302_write_seconds(second); /* start it */
+        ds1302_write_seconds(buffer[0] & 0x7F); /* start it */
     }
-
-    if(year < 70)
-        year += 100;
-
-    /* following code is based on utc_mktime() from ELKS 
-       https://github.com/jbruchon/elks/blob/master/elkscmd/sh_utils/date.c */
-
-    /* uses zero-based month index */
-    month--;
-
-    /* calculate days from years */
-    ret = multiply_8x32(year - 70, 365);
-
-    /* count leap days in preceding years */
-    ret += ((year - 69) >> 2);
-
-    /* calculate days from months */
-    ret += mktime_moffset[month];
-
-    /* add in this year's leap day, if any */
-    if (((year & 3) == 0) && (month > 1)) {
-        ret ++;
-    }
-
-    /* add in days in this month */
-    ret += (day - 1);
-
-    /* convert to hours */
-    ret = multiply_8x32(24, ret);
-    ret += hour;
-
-    /* convert to minutes */
-    ret = multiply_8x32(60, ret);
-    ret += minute;
-
-    /* convert to seconds */
-    ret = multiply_8x32(60, ret);
-    ret += second;
-
-    /* return the result */
-    return ret;
 }
 
 void ds1302_init(void)
@@ -159,8 +56,6 @@ void ds1302_init(void)
     ds1302_set_pin_data(false);
     ds1302_set_pin_ce(false);
     ds1302_set_pin_clk(false);
-
-    tod.high = 0;                   /* until 2106 */
-    tod.low = ds1302_read_rtc();
+    ds1302_check_rtc();
     wrtime(&tod);
 }