Fix CIA B timer counting A timer underflows or CNT.

diff --git a/cia.cpp b/cia.cpp
index e4c95472661006f43bcd44f1b459a9d8dc420a48..37adbe4156588452f87e95fda5a81372f03f7f50 100644 (file)
--- a/cia.cpp
+++ b/cia.cpp
@@ -407,7 +407,6 @@ static uae_u8 cia_inmode_cnt(int num)
 
        // A INMODE=1 (count CNT pulses)
        if ((c->t[0].cr & (CR_INMODE | CR_START)) == (CR_INMODE | CR_START)) {
-               c->t[0].timer--;
                if (c->t[0].timer == 0) {
                        icr |= ICR_A;
                        timer_reset(&c->t[0]);
@@ -418,6 +417,8 @@ static uae_u8 cia_inmode_cnt(int num)
                        if ((c->t[1].cr & (CR_INMODE1 | CR_START)) == (CR_INMODE1 | CR_START)) {
                                decb = true;
                        }
+               } else {
+                       c->t[0].timer--;
                }
        }
        // B INMODE=01 (count CNT pulses)
@@ -426,13 +427,14 @@ static uae_u8 cia_inmode_cnt(int num)
        }
 
        if (decb) {
-               c->t[1].timer--;
                if (c->t[1].timer == 0) {
                        icr |= ICR_B;
                        timer_reset(&c->t[1]);
                        if (c->t[1].cr & CR_RUNMODE) {
                                c->t[1].cr &= ~CR_START;
                        }
+               } else {
+                       c->t[1].timer--;
                }
        }
        return icr;
@@ -513,6 +515,7 @@ static void CIA_update_check(void)
                                        t->timer = t->latch;
                                        t->inputpipe &= ~CIA_PIPE_CLR1;
                                }
+
                                if ((t->loaddelay & 0x0100) && t->timer != 0) {
                                        loaded2[tn] = true;
                                }
@@ -531,12 +534,11 @@ static void CIA_update_check(void)
                                t->loaddelay >>= 1;
                                t->loaddelay &= 0x7f7f7f7f;
                        }
-
                }
 
                // Timer A
                int cc = 0;
-               if ((c->t[0].cr& (CR_INMODE | CR_START)) == CR_START || c->t[0].inputpipe) {
+               if ((c->t[0].cr & (CR_INMODE | CR_START)) == CR_START || c->t[0].inputpipe) {
                        cc = process_pipe(&c->t[0], ciaclocks, CR_INMODE | CR_START, &ovfl[0]);
                }
                if (cc > 0) {
@@ -555,10 +557,6 @@ static void CIA_update_check(void)
                                        }
                                }
                                ovfl[0] = 1;
-                               // B INMODE=10 or 11
-                               if ((c->t[1].cr & (CR_INMODE | CR_INMODE1 | CR_START)) == (CR_INMODE1 | CR_START) || (c->t[1].cr & (CR_INMODE | CR_INMODE1 | CR_START)) == (CR_INMODE | CR_INMODE1 | CR_START)) {
-                                       c->t[1].inputpipe |= CIA_PIPE_INPUT;
-                               }
                        }
                }
                assert(c->t[0].timer < 0x10000);
@@ -569,13 +567,22 @@ static void CIA_update_check(void)
                        cc = process_pipe(&c->t[1], ciaclocks, CR_INMODE | CR_INMODE1 | CR_START, &ovfl[1]);
                }
                if (cc > 0) {
-                       c->t[1].timer -= cc;
-                       if (c->t[1].timer == 0) {
+                       if ((c->t[1].timer == 0 && (c->t[1].cr & (CR_INMODE | CR_INMODE1)))) {
                                ovfl[1] = 1;
+                       } else {
+                               c->t[1].timer -= cc;
+                               if ((c->t[1].timer == 0 && !(c->t[1].cr & (CR_INMODE | CR_INMODE1)))) {
+                                       ovfl[1] = 1;
+                               }
                        }
                }
                assert(c->t[1].timer < 0x10000);
 
+               // B INMODE=10 or 11
+               if (ovfl[0] && ((c->t[1].cr & (CR_INMODE | CR_INMODE1 | CR_START)) == (CR_INMODE1 | CR_START) || (c->t[1].cr & (CR_INMODE | CR_INMODE1 | CR_START)) == (CR_INMODE | CR_INMODE1 | CR_START))) {
+                       c->t[1].inputpipe |= CIA_PIPE_INPUT;
+               }
+
                for (int tn = 0; tn < 2; tn++) {
                        struct CIATimer *t = &c->t[tn];
 
@@ -674,6 +681,7 @@ static void CIA_calctimers(void)
                for (int tn = 0; tn < 2; tn++) {
                        struct CIATimer *t = &c->t[tn];
                        bool timerspecial = t->loaddelay != 0;
+                       int tnidx = idx + tn;
                        if (t->cr & CR_START) {
                                if (t->inputpipe != CIA_PIPE_ALL_MASK) {
                                        timerspecial = true;
@@ -683,8 +691,8 @@ static void CIA_calctimers(void)
                                        timerspecial = true;
                                }
                        }
-                       if (timerspecial && (timevals[idx] < 0 || timevals[idx] > DIV10)) {
-                               timevals[idx + tn] = DIV10;
+                       if (timerspecial && (timevals[tnidx] < 0 || timevals[tnidx] > DIV10)) {
+                               timevals[tnidx] = DIV10;
                        }
                }
 
@@ -692,7 +700,7 @@ static void CIA_calctimers(void)
                        timevals[idx] = DIV10;
                }
 
-#if CIA_EVERY_CYCLE_DEBUG              
+#if CIA_EVERY_CYCLE_DEBUG
                timevals[idx] = DIV10;
 #endif