From: Maik Fischer <maikf@qu.cx>
Date: Wed, 1 Nov 2017 18:03:17 +0000 (+0100)
Subject: use the more accurate CIA1 Time Of Day instead of the jiffy clock
X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=3284e98234b553487eb47fe9f05ec826ccae0552;p=c128-kasse

use the more accurate CIA1 Time Of Day instead of the jiffy clock
---

diff --git a/Makefile b/Makefile
index 397c7ad..5cc4086 100644
--- a/Makefile
+++ b/Makefile
@@ -32,7 +32,7 @@ include/version.h: .git/index
 include/charset_umlauts.h: assets/umlauts.pbm
 	./util/mkfont assets/umlauts.pbm chars_umlauts > $@
 
-kasse: build/config.o build/kasse.o build/general.o build/credit_manager.o build/c128time.o build/print.o build/vdc_patch_charset.o build/vdc_util.o build/globals.o
+kasse: build/config.o build/kasse.o build/general.o build/credit_manager.o build/c128time.o build/print.o build/vdc_patch_charset.o build/vdc_util.o build/globals.o build/bcd2dec.o
 	${LD} -Ln $@.lbl -t c128 $^ -o $@
 
 itemz: build/config.o build/itemz.o build/general.o build/credit_manager.o build/c128time.o build/print.o build/globals.o
diff --git a/include/bcd2dec.h b/include/bcd2dec.h
new file mode 100644
index 0000000..f3fa98c
--- /dev/null
+++ b/include/bcd2dec.h
@@ -0,0 +1 @@
+extern uint8_t __fastcall__ bcd2dec(uint8_t bcd);
diff --git a/include/c128time.h b/include/c128time.h
index c595280..af76f84 100644
--- a/include/c128time.h
+++ b/include/c128time.h
@@ -1,5 +1,8 @@
 #ifndef TIME_H
 #define TIME_H
-void set_time(BYTE hrs, BYTE min, BYTE sec);
+#include <stdint.h>
+
+void set_time(uint8_t hrs, uint8_t min, uint8_t sec);
 char *get_time(void);
-#endif
+
+#endif /* TIME_H */
diff --git a/src/bcd2dec.s b/src/bcd2dec.s
new file mode 100644
index 0000000..3056693
--- /dev/null
+++ b/src/bcd2dec.s
@@ -0,0 +1,23 @@
+
+        .export   _bcd2dec
+        .importzp tmp1,tmp2
+
+.code
+
+;; Copied from [cc65]/libsrc/c128/systime.s
+
+.proc   _bcd2dec
+        tax
+        and     #%00001111
+        sta     tmp1
+        txa
+        and     #%11110000      ; *16
+        lsr                     ; *8
+        sta     tmp2
+        lsr
+        lsr                     ; *2
+        adc     tmp2            ; = *10
+        adc     tmp1
+        ldx     #0
+        rts
+.endproc
diff --git a/src/c128time.c b/src/c128time.c
index 9e5e458..e268133 100644
--- a/src/c128time.c
+++ b/src/c128time.c
@@ -7,33 +7,67 @@
 #include <peekpoke.h>
 #include <stdlib.h>
 #include <stdio.h>
-#include "general.h"
+#include <c128.h>
 #include <stdint.h>
 
+#include "bcd2dec.h"
+#include "general.h"
+#include "globals.h"
+
 char *get_time(void) {
-  uint32_t h = PEEK(0x00A0) * 65536, m = PEEK(0x00A1) * 256, s = PEEK(0x00A2);
   static char buffer[9];
-  BYTE hrs, min;
+  uint8_t bcd_hour, hour, bcd_min, bcd_sec, tenth;
+
+  /* Read the hour register first to stop the clock from updating the external
+   * registers from the internal (still ticking!) CIA registers. */
+
+  bcd_hour = CIA1.tod_hour;
+
+  /* if high bit is set, it is pm */
+  if (bcd_hour & 0x80) {
+    hour = bcd2dec(bcd_hour ^ 0x80);
+    /* adjust for 24h clock, 12:??pm is still 12:?? */
+    if (hour != 12) {
+      hour += 12;
+    }
+  } else {
+    hour = bcd2dec(bcd_hour);
+  }
 
-  h = (h + m + s) / 60;
-  hrs = (h / 3600);
-  h -= ((uint32_t)hrs * (uint32_t)3600);
-  min = (h / 60);
-  h -= (min * 60);
+  bcd_sec = CIA1.tod_sec;
+  bcd_min = CIA1.tod_min;
 
-  sprintf(buffer, "%02d:%02d:%02d", hrs, min, (BYTE)h);
+  /* MUST read tod_10 to enable the clock latch again */
+  tenth = CIA1.tod_10;
+
+  sprintf(buffer, "%02d:%02x:%02x", hour, bcd_min, bcd_sec);
   return buffer;
 }
 
-void set_time(BYTE hrs, BYTE min, BYTE sec) {
-  uint32_t added = ((uint32_t)sec + ((uint32_t)min * (uint32_t)60) +
-                    ((uint32_t)hrs * (uint32_t)3600)) *
-                   (uint32_t)60;
-  uint32_t lowbit = (added & 0xFF);
-  uint32_t middlebit = (added >> 8) & 0xFF;
-  uint32_t highbit = (added >> 16) & 0xFF;
-
-  POKE(0x00A0, (BYTE)highbit);
-  POKE(0x00A1, (BYTE)middlebit);
-  POKE(0x00A2, (BYTE)lowbit);
+/* divide by 10; put quotient in high nibble, reminder in low nibble */
+uint8_t dec2bcd(uint8_t dec) { return (((dec / 10) << 4) | (dec % 10)); }
+
+void set_time(uint8_t hour, uint8_t min, uint8_t sec) {
+  uint8_t bcd_hour;
+
+  /* CIA TOD will always flip the pm bit
+   * when either 0 or 12 is written to the hour register */
+  if (hour == 0) {
+    /* bcd 12 with high bit (pm) set */
+    bcd_hour = 0x92;
+  } else if (hour > 12) {
+    /* convert 24h clock to 12h with pm bit set */
+    bcd_hour = dec2bcd(hour - 12);
+    bcd_hour = bcd_hour ^ 0x80;
+  } else {
+    /* includes 12pm since the bit gets automatically flipped */
+    bcd_hour = dec2bcd(hour);
+  }
+
+  CIA1.tod_hour = bcd_hour;
+  CIA1.tod_min = dec2bcd(min);
+  CIA1.tod_sec = dec2bcd(sec);
+
+  /* set CIA1.tod_10 and program "Control Timer A" */
+  __asm__("jsr initsystime");
 }