polio: add paracomm i05 recv and i06 send

polio-main.c

@@ -0,0 +1,101 @@
+#include <stdint.h>
+
+#include "fat12.h"
+#include "paracomm.h"
+
+#define kFatAddr ((void*)0x1a00)
+#define kRootDirAddr ((void*)0x1c00)
+#define kPolmonAddr ((void*)0x1000)
+#define kInt80Vector ((uint16_t*)(0x80 * 4))
+#define kParallelDataPort 0x3bc
+#define kParallelStatusPort 0x3bd
+#define kParallelControlPort 0x3be
+#define kParaDelay 400
+
+void dosdbt();
+void int80h();
+
+uint8_t* parabuf;
+uint8_t parasize;
+
+static void paracb(const uint8_t* buf, uint8_t size) {
+    if (size > parasize) {
+        return paracb(buf, parasize);
+    }
+    for (int i = 0; i < size; i++) {
+        parabuf[i] = buf[i];
+    }
+    parasize = 0;
+}
+
+static void die() {
+    while (1) {
+    }
+}
+
+static void __outb__(uint16_t port, uint8_t data) {
+    register uint16_t p asm("dx") = port;
+    register uint8_t d asm("al") = data;
+    asm volatile("outb %0, %1" ::"r"(d), "r"(p));
+}
+
+static uint8_t __inb__(uint16_t port) {
+    register uint16_t p asm("dx") = port;
+    register uint8_t d asm("al");
+    asm volatile("inb %1, %0" : "=r"(d) : "r"(p));
+    return d;
+}
+
+static void __delay__(int n) {
+    for (int i = 0; i < n; i++) {
+        asm volatile("");
+    }
+}
+
+static void paraxfer() {
+    uint8_t mosib = paracomm_nextbyte();
+    __outb__(kParallelDataPort, mosib);
+    __outb__(kParallelControlPort, 1);
+    __delay__(kParaDelay);
+    __outb__(kParallelControlPort, 0);
+    __delay__(kParaDelay);
+    uint8_t mison = __inb__(kParallelStatusPort) >> 4;
+    paracomm_feed(mison);
+}
+
+void pararecv(uint8_t* addr, uint8_t size) {
+    parabuf = addr;
+    parasize = size;
+    for (int i = 0; i < 1 + 2 + size * 2; i++) {
+        if (!parasize) {
+            break;
+        }
+        paraxfer();
+    }
+}
+
+void parasend(uint8_t* addr, uint8_t size) {
+    for (int i = 0; i < size; i++) {
+        paracomm_send(addr[i]);
+    }
+    for (int i = 0; i < size + 2; i++) {
+        paraxfer();
+    }
+}
+
+int main() {
+    dosdbt();
+    paracomm_init(paracb);
+
+    fat12_init(kFatAddr, kRootDirAddr);
+
+    uint16_t* int80v = kInt80Vector;
+    int80v[0] = (uint16_t)int80h;
+    int80v[1] = 0;
+
+    if (fat12_readfile("POLMON  COM", kPolmonAddr)) {
+        die();
+    }
+
+    asm volatile("jmp *%0" ::"r"(kPolmonAddr));
+}