From 9e6f6c5a67db16949d1183d03075a528f23590ae Mon Sep 17 00:00:00 2001
From: Toby Jaffey <toby@ringtailsoftware.co.uk>
Date: Sun, 7 Dec 2025 20:29:10 +0000
Subject: [PATCH] Added IOREQ_MILLIS and IOREQ_GETC to get current time and
 poll keyboard. IOREQ_GETC implemented inefficiently, but is fine for demo
 purposes.

---
 common/uvm32_common_custom.h |  1 +
 host/Makefile                |  2 +-
 host/host.c                  | 90 +++++++++++++++++++++++++++++++++---
 3 files changed, 86 insertions(+), 7 deletions(-)

diff --git a/common/uvm32_common_custom.h b/common/uvm32_common_custom.h
index e5c0a35..7f6d0a8 100644
--- a/common/uvm32_common_custom.h
+++ b/common/uvm32_common_custom.h
@@ -7,4 +7,5 @@
 #define IOREQ_PRINTX 0x13D
 #define IOREQ_MILLIS 0x13F
 #define IOREQ_PRINTC 0x140
+#define IOREQ_GETC 0x141
 
diff --git a/host/Makefile b/host/Makefile
index 0adb487..d31fa90 100644
--- a/host/Makefile
+++ b/host/Makefile
@@ -1,5 +1,5 @@
 all:
-	gcc -Wall -Werror -pedantic -std=c99 -DUVM32_MEMORY_SIZE=16384 -I../uvm32 -o host ../uvm32/uvm32.c host.c
+	gcc -Wall -Werror -pedantic -std=c99 -O2 -DUVM32_MEMORY_SIZE=65535 -I../uvm32 -o host ../uvm32/uvm32.c host.c
 
 clean:
 	rm -f host
diff --git a/host/host.c b/host/host.c
index d342558..0370e08 100644
--- a/host/host.c
+++ b/host/host.c
@@ -1,11 +1,16 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-
+#include <time.h>
+#include <unistd.h>
+#include <termios.h>
 #include "uvm32.h"
 
 #include "../common/uvm32_common_custom.h"
 
+// stash terminal settings on startup
+static struct termios orig_termios;
+
 // ioreqs exposed to vm environement
 typedef enum {
     F_PRINT,
@@ -14,6 +19,7 @@ typedef enum {
     F_PRINTC,
     F_PRINTLN,
     F_MILLIS,
+    F_GETC,
 } f_code_t;
 
 // Map exposed ioreqs to CSRs
@@ -24,8 +30,24 @@ const uvm32_mapping_t env[] = {
     { .csr = IOREQ_PRINTX, .typ = IOREQ_TYP_U32_WR, .code = F_PRINTX },
     { .csr = IOREQ_PRINTC, .typ = IOREQ_TYP_U32_WR, .code = F_PRINTC },
     { .csr = IOREQ_MILLIS, .typ = IOREQ_TYP_U32_RD, .code = F_MILLIS },
+    { .csr = IOREQ_GETC, .typ = IOREQ_TYP_U32_RD, .code = F_GETC },
 };
 
+void disableRawMode(void) {
+    tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios);
+}
+void enableRawMode(void) {
+    tcgetattr(STDIN_FILENO, &orig_termios);
+    atexit(disableRawMode);
+    struct termios raw = orig_termios;
+    raw.c_lflag &= ~(ECHO | ICANON | IEXTEN);
+    raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+    raw.c_cflag |= (CS8);
+    tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw);
+    raw.c_cc[VMIN] = 0;
+    raw.c_cc[VTIME] = 1;
+}
+
 static uint8_t *read_file(const char* filename, int *len) {
     FILE* f = fopen(filename, "rb");
     uint8_t *buf = NULL;
@@ -56,15 +78,60 @@ static uint8_t *read_file(const char* filename, int *len) {
     return buf;
 }
 
+// Poll for input, inelegant, but works and doesn't confuse the main
+// flow of the program with select/poll
+bool poll_getch(uint8_t* c) {
+    struct timeval tv;
+    fd_set readfds;
+    int ret;
+
+    FD_ZERO(&readfds);
+    FD_SET(STDIN_FILENO, &readfds);
+
+    tv.tv_sec = 0;
+    tv.tv_usec = 200;
+
+    ret = select(STDIN_FILENO + 1, &readfds, NULL, NULL, &tv);
+
+    if (ret == -1) {
+        printf("console read failed\r\n");
+        exit(1);
+    } else if (!ret) {
+        // timeout
+        return false;
+    }
+
+    if (FD_ISSET(STDIN_FILENO, &readfds)) {
+        int len;
+
+        len = read(STDIN_FILENO, c, 1);
+        if (len == -1) {
+            printf("console read failed\r\n");
+            exit(1);
+        }
+
+        if (len) {
+            if (*c == 0x03 || *c == 0x04) {   // ctrl-c ctrl-d
+                exit(0);
+            }
+            if (*c == 0x0d) {
+                *c = '\n';
+            }
+            return true;
+        }
+    }
+    return false;
+}
+
 void hexdump(const uint8_t *p, int len) {
     while(len--) {
         printf("%02x", *p++);
     }
 }
 
-
 int main(int argc, char *argv[]) {
     uvm32_state_t vmst;
+    clock_t start_time = clock() / (CLOCKS_PER_SEC / 1000);
 
     argc--;
     argv++;
@@ -92,8 +159,10 @@ int main(int argc, char *argv[]) {
     uint32_t total_instrs = 0;
     uint32_t num_ioreqs = 0;
 
+    enableRawMode();
+
     while(isrunning) {
-        total_instrs += uvm32_run(&vmst, &evt, 100);   // num instructions before vm considered hung
+        total_instrs += uvm32_run(&vmst, &evt, 1000000);   // num instructions before vm considered hung
         num_ioreqs++;
 
         switch(evt.typ) {
@@ -126,10 +195,17 @@ int main(int argc, char *argv[]) {
                     case F_PRINTX:
                         printf("%08x", evt.data.ioreq.val.u32);
                     break;
+                    case F_GETC: {
+                        uint8_t ch;
+                        if (poll_getch(&ch)) {
+                            *evt.data.ioreq.val.u32p = ch;
+                        } else {
+                            *evt.data.ioreq.val.u32p = 0xFFFFFFFF;  // nothing
+                        }
+                    } break;
                     case F_MILLIS: {
-                        static uint32_t t = 0;
-                        *evt.data.ioreq.val.u32p = t;
-                        t++;
+                        clock_t now = clock() / (CLOCKS_PER_SEC / 1000);
+                        *evt.data.ioreq.val.u32p = now - start_time;
                     } break;
                     default:    // catch any others
                         switch(evt.data.ioreq.typ) {
@@ -162,5 +238,7 @@ int main(int argc, char *argv[]) {
     printf("Executed total of %d instructions and %d ioreqs\n", (int)total_instrs, (int)num_ioreqs);
 
     free(rom);
+
+    disableRawMode();
     return 0;
 }