--- nono/vm/crtc.cpp	2026/04/29 17:04:31	1.1.1.3
+++ nono/vm/crtc.cpp	2026/04/29 17:04:35	1.1.1.4
@@ -1,6 +1,7 @@
 //
 // nono
-// Copyright (C) 2017 isaki@NetBSD.org
+// Copyright (C) 2020 nono project
+// Licensed under nono-license.txt
 //
 
 #include "crtc.h"
@@ -8,6 +9,15 @@
 #include "renderer.h"
 #include "tvram.h"
 
+// e80000..e803ff 内は $40 バイトでミラー。
+// e80400..e807ff 内は 256 バイトでミラーになっており、このうち
+// +$00..+$7f はバスエラー、
+// +$80..+$ff は何かが読める。
+// 仕様は $e80480.w に1ポートあるので、これがワードで全域にミラーされている?
+// 全体としては この $800 バイトずつが繰り返して見える。
+
+std::unique_ptr<CRTCDevice> gCRTC;
+
 CRTCDevice::CRTCDevice()
 {
 	logname = "crtc";
@@ -38,149 +48,121 @@ CRTCDevice::ResetHard()
 }
 
 uint64
-CRTCDevice::Read8(uint32 addr)
+CRTCDevice::Read(uint32 addr)
 {
-	uint32 an = (addr - devaddr) / 2;
-	uint16 data;
+	uint64 data;
 
-	switch (an) {
-	 case CRTC::R00 ... CRTC::R23:
-		data = crtc.r[an];
-		if ((addr & 1) == 0) {
-			data >>= 8;
-			putlog(2, "R%02d(H) -> $%02x", an, data);
-		} else {
-			data &= 0xff;
-			putlog(2, "R%02d(L) -> $%02x", an, data);
+	if (addr < 0x400 / 2) {		// CRTC レジスタ
+		// 0x40 バイトでミラー
+		addr &= (0x40 / 2) - 1;
+		// R20, R21 のみ読み出し可能
+		switch (addr) {
+		 case 20:
+			data = crtc.r[addr];
+			putlog(2, "R%02d -> $%04x", addr, (uint32)data);
+			break;
+		 case 21:
+			// R21 へのアクセスは多いのでログレベルを上げておく
+			data = crtc.r[addr];
+			putlog(3, "R%02d -> $%04x", addr, (uint32)data);
+			break;
+		 default:
+			// それ以外は読み出し不可 ($00 が読める)
+			data = 0;
+			if (addr < countof(crtc.r)) {
+				putlog(3, "R%02d -> $%04x", addr, (uint32)data);
+			} else {
+				putlog(3, "$%06x -> $%04x", gMPU->GetPaddr(), (uint32)data);
+			}
+			break;
 		}
-		break;
 
-	 case CRTC::REG_OP:	// $E80480
-		data = crtc.op;
-		if ((addr & 1) == 0) {
-			data >>= 8;
-			putlog(2, "$E80480 -> $%02x", data);
-		} else {
-			data &= 0xff;
-			putlog(2, "$E80481 -> $%02x", data);
+	} else {					// 動作ポート
+		if ((addr & (0x80 / 2)) == 0) {	// +$00..+$7f
+			data = (uint64)-1;
+		} else {						// +$80..+$ff
+			data = crtc.op;
 		}
-		break;
-
-	 default:
-		putlog(1, "Read8 $%06x 未実装ポート読み込み", addr);
-		data = 0xff;
 	}
 
 	return data;
 }
 
 uint64
-CRTCDevice::Read16(uint32 addr)
+CRTCDevice::Write(uint32 addr, uint32 data)
 {
-	uint32 an = (addr - devaddr) / 2;
-	uint16 data;
-
-	switch (an) {
-	 case CRTC::R00 ... CRTC::R23:
-		data = crtc.r[an];
-		putlog(2, "R%02d -> $%04x", an, data);
-		return data;
-
-	 default:
-		putlog(1, "$%06x 未実装読み込み", addr);
-		return 0;
-	}
-}
-
-uint64
-CRTCDevice::Write8(uint32 addr, uint32 data)
-{
-	uint32 an = (addr - devaddr) / 2;
-
-	switch (an) {
-	 case CRTC::R00 ... CRTC::R23:
-		// 16ビットにしてから書き込む
-		if((addr & 1) == 0) {
-			data = (data << 8) | (crtc.r[an] & 0x00ff);
-			putlog(2, "R%02d(H) = $%04x", an, data);
+	if (addr < 0x400 / 2) {		// CRTC レジスタ
+		// 0x40 バイトでミラー
+		addr &= (0x40 / 2) - 1;
+		if (addr < countof(crtc.r)) {
+			SetReg(addr, data);
 		} else {
-			data = (data & 0xff) | (crtc.r[an] & 0xff00);
-			putlog(2, "R%02d(L) = $%04x", an, data);
+			// ここ何がいるんだ?
+			putlog(2, "$%06x <- $%04x", gMPU->GetPaddr(), data);
 		}
-		WriteReg(an, data);
-		break;
 
-	 case CRTC::REG_OP:
-		// 下位8ビットのみ有効
-		if ((addr & 1) == 1) {
-			putlog(2, "$E80481 <- $%02x", data);
+	} else {					// 動作ポート
+		if ((addr & (0x80 / 2)) == 0) {	// +$00..+$7f
+			return (uint64)-1;
+		} else {
 			crtc.op = data & 0x0b;
+			putlog(2, "$E80480.W <- $%04x", crtc.op);
 		}
-		break;
-
-	 default:
-		putlog(1, "Write8 $%06x <- $%02x 未実装書き込み", addr, data);
-		break;
 	}
+
 	return 0;
 }
 
 uint64
-CRTCDevice::Write16(uint32 addr, uint32 data)
+CRTCDevice::Peek(uint32 addr)
 {
-	uint32 an = (addr - devaddr) / 2;
+	uint64 data;
 
-	switch (an) {
-	 case CRTC::R00 ... CRTC::R23:
-		putlog(2, "R%02d <- $%04x", an, data);
-		WriteReg(an, data);
-		break;
-
-	 case CRTC::REG_OP:
-		putlog(2, "$E80481 <- $%02x", data);
-		crtc.op = data & 0x0b;
-		break;
+	if (addr < 0x400 / 2) {		// CRTC レジスタ
+		// 0x40 バイトでミラー
+		addr &= (0x40 / 2) - 1;
+		if (addr == 20 || addr == 21) {
+			// R20, R21 のみ読み出し可能
+			data = crtc.r[addr];
+		} else {
+			data = 0;
+		}
 
-	 default:
-		putlog(1, "$%06x <- $%04x 未実装書き込み", addr, data);
-		break;
+	} else {					// 動作ポート
+		if ((addr & (0x80 / 2)) == 0) {
+			data = (uint64)-1;
+		} else {
+			data = crtc.op;
+		}
 	}
-	return 0;
+
+	return data;
 }
 
-// Write8/16 の下請け。内部アクセス用
-// offset は CRTC::R00 .. CRTC::R23
+// CRTC レジスタへの書き込み。
+// reg は CRTC::R00 .. CRTC::R23
 void
-CRTCDevice::WriteReg(uint32 reg, uint32 data)
+CRTCDevice::SetReg(uint32 reg, uint32 data)
 {
 	crtc.r[reg] = data;
 
 	switch (reg) {
+	 case CRTC::R10:
+		putlog(2, "R%02d <- $%04x", reg, data);
+		gTVRAM->SetScrollX(crtc.r[10]);
+		break;
+	 case CRTC::R11:
+		putlog(2, "R%02d <- $%04x", reg, data);
+		gTVRAM->SetScrollY(crtc.r[11]);
+		break;
 	 case CRTC::R21:
+		// 頻度が高いのでログレベルを上げておく
+		putlog(3, "R%02d <- $%04x", reg, data);
 		gTVRAM->set_crtc_21(crtc.r[21]);
 		break;
-	}
-}
-
-uint64
-CRTCDevice::Peek8(uint32 addr)
-{
-	uint32 an2 = addr - devaddr;
-
-	switch (an2) {
-	 case CRTC::R00 ... (CRTC::R23 * 2 + 1):
-		if ((an2 & 1) == 0) {
-			return crtc.r[an2 / 2] >> 8;
-		} else {
-			return crtc.r[an2 / 2] & 0xff;
-		}
-		break;
-
-	 case CRTC::REG_OP * 2 + 1:
-		return crtc.op;
-
 	 default:
-		return 0xff;
+		putlog(2, "R%02d <- $%04x (未実装)", reg, data);
+		break;
 	}
 }