From 7603ddf9cc694925ab6b36bdb230de3ab741e478 Mon Sep 17 00:00:00 2001
From: Devine Lu Linvega <aliceffekt@gmail.com>
Date: Sat, 28 Jan 2023 16:47:41 -0800
Subject: [PATCH] Added MMU operation

---
 src/devices/system.c | 50 +++++++++++++++++++++++++++++++++++---------
 src/devices/system.h |  6 ++++++
 src/uxn11.c          |  3 ++-
 src/uxncli.c         |  9 ++++----
 4 files changed, 53 insertions(+), 15 deletions(-)

diff --git a/src/devices/system.c b/src/devices/system.c
index f1607cd..5339c41 100644
--- a/src/devices/system.c
+++ b/src/devices/system.c
@@ -1,10 +1,11 @@
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "../uxn.h"
 #include "system.h"
 
 /*
-Copyright (c) 2022 Devine Lu Linvega, Andrew Alderwick
+Copyright (c) 2022-2023 Devine Lu Linvega, Andrew Alderwick
 
 Permission to use, copy, modify, and distribute this software for any
 purpose with or without fee is hereby granted, provided that the above
@@ -42,27 +43,56 @@ int
 uxn_halt(Uxn *u, Uint8 instr, Uint8 err, Uint16 addr)
 {
 	Uint8 *d = &u->dev[0x00];
-	if(instr & 0x40)
-		u->rst->err = err;
-	else
-		u->wst->err = err;
-	if(GETVEC(d))
-		uxn_eval(u, GETVEC(d));
-	else {
+	Uint16 handler = GETVEC(d);
+	if(handler) {
+		u->wst->ptr = 4;
+		u->wst->dat[0] = addr >> 0x8;
+		u->wst->dat[1] = addr & 0xff;
+		u->wst->dat[2] = instr;
+		u->wst->dat[3] = err;
+		return uxn_eval(u, handler);
+	} else {
 		system_inspect(u);
 		fprintf(stderr, "%s %s, by %02x at 0x%04x.\n", (instr & 0x40) ? "Return-stack" : "Working-stack", errors[err - 1], instr, addr);
 	}
 	return 0;
 }
 
+/* MMU */
+
+Uint8 *
+mmu_init(Mmu *m, Uint16 pages)
+{
+	m->length = pages;
+	m->pages = (Uint8 *)calloc(0x10000 * pages, sizeof(Uint8));
+	return m->pages;
+}
+
+void
+mmu_eval(Uint8 *ram, Uint16 addr)
+{
+	Uint16 a = addr, i = 0;
+	Uint8 o = ram[a++];
+	if(o == 1) {
+		Uint16 length = (ram[a++] << 8) + ram[a++];
+		Uint16 src_page = ((ram[a++] << 8) + ram[a++]) % 16, src_addr = (ram[a++] << 8) + ram[a++];
+		Uint16 dst_page = ((ram[a++] << 8) + ram[a++]) % 16, dst_addr = (ram[a++] << 8) + ram[a];
+		for(i = 0; i < length; i++)
+			ram[dst_page * 0x10000 + dst_addr + i] = ram[src_page * 0x10000 + src_addr + i];
+	}
+}
+
 /* IO */
 
 void
 system_deo(Uxn *u, Uint8 *d, Uint8 port)
 {
+	Uint16 a;
 	switch(port) {
-	case 0x2: u->wst = (Stack *)(u->ram + (d[port] ? (d[port] * 0x100) : 0x10000)); break;
-	case 0x3: u->rst = (Stack *)(u->ram + (d[port] ? (d[port] * 0x100) : 0x10100)); break;
+	case 0x3:
+		PEKDEV(a, 0x2);
+		mmu_eval(u->ram, a);
+		break;
 	case 0xe:
 		if(u->wst->ptr || u->rst->ptr) system_inspect(u);
 		break;
diff --git a/src/devices/system.h b/src/devices/system.h
index 9d8117d..6be1005 100644
--- a/src/devices/system.h
+++ b/src/devices/system.h
@@ -11,3 +11,9 @@ WITH REGARD TO THIS SOFTWARE.
 
 void system_inspect(Uxn *u);
 void system_deo(Uxn *u, Uint8 *d, Uint8 port);
+
+typedef struct {
+	Uint8 length, *pages;
+} Mmu;
+
+Uint8 *mmu_init(Mmu *m, Uint16 pages);
diff --git a/src/uxn11.c b/src/uxn11.c
index a137766..01dafa1 100644
--- a/src/uxn11.c
+++ b/src/uxn11.c
@@ -225,6 +225,7 @@ int
 main(int argc, char **argv)
 {
 	Uxn u;
+	Mmu m;
 	int i;
 	char expirations[8];
 	struct pollfd fds[2];
@@ -232,7 +233,7 @@ main(int argc, char **argv)
 	if(argc < 2)
 		return emu_error("Usage", "uxn11 game.rom args");
 	rom_path = argv[1];
-	if(!uxn_boot(&u, (Uint8 *)calloc(0x10300, sizeof(Uint8)), emu_dei, emu_deo))
+	if(!uxn_boot(&u, mmu_init(&m, 16), emu_dei, emu_deo))
 		return emu_error("Boot", "Failed");
 	/* start sequence */
 	if(!emu_start(&u, rom_path))
diff --git a/src/uxncli.c b/src/uxncli.c
index 4a4538c..94d7935 100644
--- a/src/uxncli.c
+++ b/src/uxncli.c
@@ -7,7 +7,7 @@
 #include "devices/datetime.h"
 
 /*
-Copyright (c) 2021 Devine Lu Linvega
+Copyright (c) 2021-2023 Devine Lu Linvega, Andrew Alderwick
 
 Permission to use, copy, modify, and distribute this software for any
 purpose with or without fee is hereby granted, provided that the above
@@ -37,8 +37,8 @@ console_input(Uxn *u, char c)
 static void
 console_deo(Uint8 *d, Uint8 port)
 {
-	FILE *fd = port == 0x8 ? stdout : port == 0x9 ? stderr :
-													0;
+	FILE *fd = port == 0x8 ? stdout : port == 0x9 ? stderr
+												  : 0;
 	if(fd) {
 		fputc(d[port], fd);
 		fflush(fd);
@@ -78,9 +78,10 @@ main(int argc, char **argv)
 {
 	Uxn u;
 	int i;
+	Mmu mmu;
 	if(argc < 2)
 		return emu_error("Usage", "uxncli game.rom args");
-	if(!uxn_boot(&u, (Uint8 *)calloc(0x10300, sizeof(Uint8)), emu_dei, emu_deo))
+	if(!uxn_boot(&u, mmu_init(&mmu, 16), emu_dei, emu_deo))
 		return emu_error("Boot", "Failed");
 	if(!load_rom(&u, argv[1]))
 		return emu_error("Load", "Failed");