diff mbox series

[23/36] next-cube: always use retval to return rtc read values

Message ID 20241023085852.1061031-24-mark.cave-ayland@ilande.co.uk
State New
Headers show
Series next-cube: more tidy-ups and improvements | expand

Commit Message

Mark Cave-Ayland Oct. 23, 2024, 8:58 a.m. UTC
Instead of shifting out rtc read values from individual rtc registers, change
the logic so that rtc read commands are executed when the last bit of the rtc
command is received and the result stored in retval. This simplifies the rtc
read logic such that the shift out logic can be consolidated for rtc phases
between 8 and 16.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 hw/m68k/next-cube.c | 99 ++++++++++++++++++---------------------------
 1 file changed, 40 insertions(+), 59 deletions(-)
diff mbox series

Patch

diff --git a/hw/m68k/next-cube.c b/hw/m68k/next-cube.c
index 4aed80c9fe..bca975065f 100644
--- a/hw/m68k/next-cube.c
+++ b/hw/m68k/next-cube.c
@@ -190,93 +190,74 @@  static void next_scr2_rtc_update(NeXTPC *s)
             if (rtc->phase < 8) {
                 rtc->command = (rtc->command << 1) |
                                ((scr2_2 & SCR2_RTDATA) ? 1 : 0);
-            }
-            if (rtc->phase >= 8 && rtc->phase < 16) {
-                if (next_rtc_cmd_is_write(rtc->command)) {
-                    /* Shift in value to write */
-                    rtc->value = (rtc->value << 1) |
-                                 ((scr2_2 & SCR2_RTDATA) ? 1 : 0);
-                } else {
-                    /* Shift out value to read */
 
-                    /* if we read RAM register, output RT_DATA bit */
-                    if (rtc->command <= 0x1F) {
-                        scr2_2 = scr2_2 & (~SCR2_RTDATA);
-                        if (rtc->ram[rtc->command] &
-                            (0x80 >> (rtc->phase - 8))) {
-                                scr2_2 |= SCR2_RTDATA;
-                        }
-
-                        rtc->retval = (rtc->retval << 1) |
-                                      ((scr2_2 & SCR2_RTDATA) ? 1 : 0);
-                    }
-                    /* read the status 0x30 */
-                    if (rtc->command == 0x30) {
-                        scr2_2 = scr2_2 & (~SCR2_RTDATA);
-                        /* for now status = 0x98 (new rtc + FTU) */
-                        if (rtc->status & (0x80 >> (rtc->phase - 8))) {
-                            scr2_2 |= SCR2_RTDATA;
-                        }
-
-                        rtc->retval = (rtc->retval << 1) |
-                                      ((scr2_2 & SCR2_RTDATA) ? 1 : 0);
-                    }
-                    /* read the status 0x31 */
-                    if (rtc->command == 0x31) {
-                        scr2_2 = scr2_2 & (~SCR2_RTDATA);
-                        if (rtc->control & (0x80 >> (rtc->phase - 8))) {
-                            scr2_2 |= SCR2_RTDATA;
-                        }
-                        rtc->retval = (rtc->retval << 1) |
-                                      ((scr2_2 & SCR2_RTDATA) ? 1 : 0);
+                if (rtc->phase == 7 && !next_rtc_cmd_is_write(rtc->command)) {
+                    if (rtc->command <= 0x1f) {
+                        /* RAM registers */
+                        rtc->retval = rtc->ram[rtc->command];
                     }
-
                     if ((rtc->command >= 0x20) && (rtc->command <= 0x2F)) {
-                        scr2_2 = scr2_2 & (~SCR2_RTDATA);
-                        /* for now 0x00 */
+                        /* RTC */
                         time_t time_h = time(NULL);
                         struct tm *info = localtime(&time_h);
-                        int ret = 0;
+                        rtc->retval = 0;
 
                         switch (rtc->command) {
                         case 0x20:
-                            ret = SCR2_TOBCD(info->tm_sec);
+                            rtc->retval = SCR2_TOBCD(info->tm_sec);
                             break;
                         case 0x21:
-                            ret = SCR2_TOBCD(info->tm_min);
+                            rtc->retval = SCR2_TOBCD(info->tm_min);
                             break;
                         case 0x22:
-                            ret = SCR2_TOBCD(info->tm_hour);
+                            rtc->retval = SCR2_TOBCD(info->tm_hour);
                             break;
                         case 0x24:
-                            ret = SCR2_TOBCD(info->tm_mday);
+                            rtc->retval = SCR2_TOBCD(info->tm_mday);
                             break;
                         case 0x25:
-                            ret = SCR2_TOBCD((info->tm_mon + 1));
+                            rtc->retval = SCR2_TOBCD((info->tm_mon + 1));
                             break;
                         case 0x26:
-                            ret = SCR2_TOBCD((info->tm_year - 100));
+                            rtc->retval = SCR2_TOBCD((info->tm_year - 100));
                             break;
                         }
-
-                        if (ret & (0x80 >> (rtc->phase - 8))) {
-                            scr2_2 |= SCR2_RTDATA;
-                        }
-                        rtc->retval = (rtc->retval << 1) |
-                                      ((scr2_2 & SCR2_RTDATA) ? 1 : 0);
+                    }
+                    if (rtc->command == 0x30) {
+                        /* read the status 0x30 */
+                        rtc->retval = rtc->status;
+                    }
+                    if (rtc->command == 0x31) {
+                        /* read the control 0x31 */
+                        rtc->retval = rtc->control;
+                    }
+                }
+            }
+            if (rtc->phase >= 8 && rtc->phase < 16) {
+                if (next_rtc_cmd_is_write(rtc->command)) {
+                    /* Shift in value to write */
+                    rtc->value = (rtc->value << 1) |
+                                 ((scr2_2 & SCR2_RTDATA) ? 1 : 0);
+                } else {
+                    /* Shift out value to read */
+                    if (rtc->retval & (0x80 >> (rtc->phase - 8))) {
+                        scr2_2 |= SCR2_RTDATA;
+                    } else {
+                        scr2_2 &= ~SCR2_RTDATA;
                     }
                 }
             }
 
             rtc->phase++;
-            if (rtc->phase == 16) {
-                if (rtc->command >= 0x80 && rtc->command <= 0x9F) {
+            if (rtc->phase == 16 && next_rtc_cmd_is_write(rtc->command)) {
+                if (rtc->command >= 0x80 && rtc->command <= 0x9f) {
+                    /* RAM registers */
                     rtc->ram[rtc->command - 0x80] = rtc->value;
                 }
-                /* write to x30 register */
-                if (rtc->command == 0xB1) {
-                    /* clear FTU */
+                if (rtc->command == 0xb1) {
+                    /* write to 0x30 register */
                     if (rtc->value & 0x04) {
+                        /* clear FTU */
                         rtc->status = rtc->status & (~0x18);
                         qemu_irq_lower(s->rtc_power_irq);
                     }