From 730af4dd536b2d043c7aa13405bc4dc332adbced Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Thu, 4 Aug 2022 23:52:25 +0200
Subject: [PATCH] Implemented more previously unimplemented AT NVR behavior.

---
 src/nvr_at.c | 36 +++++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/src/nvr_at.c b/src/nvr_at.c
index bb4c38b85..eb749ff49 100644
--- a/src/nvr_at.c
+++ b/src/nvr_at.c
@@ -467,10 +467,10 @@ timer_update(void *priv)
 		nvr->regs[RTC_REGC] |= REGC_AF;
 		if (nvr->regs[RTC_REGB] & REGB_AIE) {
 			/* Generate an interrupt. */
-			if ((nvr->irq != -1) && (!(nvr->regs[RTC_REGC] & REGC_IRQF)))
-				picint(1 << nvr->irq);
-
-			nvr->regs[RTC_REGC] |= REGC_IRQF;
+			if ((nvr->irq != -1) && (!(nvr->regs[RTC_REGC] & REGC_IRQF))) {
+				picintlevel(1 << nvr->irq);
+				nvr->regs[RTC_REGC] |= REGC_IRQF;
+			}
 		}
 	}
 
@@ -481,10 +481,10 @@ timer_update(void *priv)
 	nvr->regs[RTC_REGC] |= REGC_UF;
 	if (nvr->regs[RTC_REGB] & REGB_UIE) {
 		/* Generate an interrupt. */
-		if ((nvr->irq != -1) && (!(nvr->regs[RTC_REGC] & REGC_IRQF)))
-			picint(1 << nvr->irq);
-
-		nvr->regs[RTC_REGC] |= REGC_IRQF;
+		if ((nvr->irq != -1) && (!(nvr->regs[RTC_REGC] & REGC_IRQF))) {
+			picintlevel(1 << nvr->irq);
+			nvr->regs[RTC_REGC] |= REGC_IRQF;
+		}
 	}
     }
 }
@@ -533,10 +533,10 @@ timer_intr(void *priv)
 	nvr->regs[RTC_REGC] |= REGC_PF;
 	if (nvr->regs[RTC_REGB] & REGB_PIE) {
 		/* Generate an interrupt. */
-		if ((nvr->irq != -1) && (!(nvr->regs[RTC_REGC] & REGC_IRQF)))
-			picint(1 << nvr->irq);
-
-		nvr->regs[RTC_REGC] |= REGC_IRQF;
+		if ((nvr->irq != -1) && (!(nvr->regs[RTC_REGC] & REGC_IRQF))) {
+			picintlevel(1 << nvr->irq);
+			nvr->regs[RTC_REGC] |= REGC_IRQF;
+		}
 	}
     }
 }
@@ -592,6 +592,7 @@ nvr_reg_write(uint16_t reg, uint8_t val, void *priv)
     local_t *local = (local_t *)nvr->data;
     struct tm tm;
     uint8_t old;
+    uint8_t irq = 0, old_irq = 0;
 
     old = nvr->regs[reg];
     switch(reg) {
@@ -601,12 +602,21 @@ nvr_reg_write(uint16_t reg, uint8_t val, void *priv)
 		break;
 
 	case RTC_REGB:
+		old_irq = (nvr->regs[RTC_REGB] & nvr->regs[RTC_REGC]) & 0x70;
 		nvr->regs[RTC_REGB] = val;
 		if (((old^val) & REGB_SET) && (val & REGB_SET)) {
 			/* According to the datasheet... */
 			nvr->regs[RTC_REGA] &= ~REGA_UIP;
 			nvr->regs[RTC_REGB] &= ~REGB_UIE;
 		}
+		irq = (nvr->regs[RTC_REGB] & nvr->regs[RTC_REGC]) & 0x70;
+		if (old_irq && !irq) {
+			picintc(1 << nvr->irq);
+			nvr->regs[RTC_REGC] &= ~REGC_IRQF;
+		} else if (!old_irq && irq) {
+			picintlevel(1 << nvr->irq);
+			nvr->regs[RTC_REGC] |= REGC_IRQF;
+		}
 		break;
 
 	case RTC_REGC:		/* R/O */
@@ -694,8 +704,8 @@ nvr_read(uint16_t addr, void *priv)
 		break;
 
 	case RTC_REGC:
-		picintc(1 << nvr->irq);
 		ret = nvr->regs[RTC_REGC];
+		picintc(1 << nvr->irq);
 		nvr->regs[RTC_REGC] = 0x00;
 		break;