some progress on dos vesa, but not quite

Common/Std/dos.c

@@ -0,0 +1,80 @@
+#include "../std.h"
+#include <assert.h>
+#include <stdarg.h>
+#include <stdint.h>
+
+#include "any.c"
+#include "nolibc.c"
+
+// void *com_std_alloc(void *ptr, size_t size) {
+//   return size != 0 ? realloc(ptr, size) : (free(ptr), NULL);
+// }
+
+// double com_std_sqrt(double v) { return sqrt(v); }
+// double com_std_fabs(double v) { return fabs(v); }
+// double com_std_sin(double v) { return sin(v); }
+// double com_std_cos(double v) { return cos(v); }
+
+// com_std_fd com_std_open(char const *path, uint32_t flags) {
+//   com_std_assert(flags != 0);
+//   char *mode = flags & COM_STD_OPEN_READ && flags & COM_STD_OPEN_WRITE ? "r+"
+//                : flags & COM_STD_OPEN_READ                             ? "r"
+//                                                                        : "w";
+//   return fopen(path, mode);
+// }
+
+bool com_std_write(com_std_fd fd, void const *data, uint32_t bytes) {
+  uint32_t written;
+  bool carry_clear;
+  __asm__ volatile("int $0x21"
+                   : "=a"(written), "=@ccnc"(carry_clear)
+                   : "a"(0x4000), "b"(fd), "c"(bytes), "d"(data)
+                   : "memory", "cc");
+  return !carry_clear && written == bytes;
+}
+
+// int32_t com_std_read(com_std_fd fd, void *data, uint32_t upto) {
+//   com_std_assert(data != NULL && upto != 0);
+//   return fread(data, 1, upto, fd);
+// }
+
+// bool com_std_has_data(com_std_fd fd) {
+//   struct pollfd pfd = {.fd = (intptr_t)fd, .events = POLLIN};
+//   int ret = poll(&pfd, 1, 0);
+//   if (ret > 0) {
+//     return pfd.revents & POLLIN;
+//   } else
+//     return false;
+// }
+
+// bool com_std_sfwd(com_std_fd fd, uint32_t bytes) {
+//   com_std_assert(fd != NULL && bytes != 0);
+//   return fseek(fd, bytes, SEEK_CUR) == 0;
+// }
+
+// com_std_fd com_std_socket(bool isnetwork) {
+//   if (!isnetwork) {
+//     int sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
+//     return fdopen(sockfd, "w+b");
+//   } else
+//     return NULL;
+// }
+
+// bool com_std_connect(com_std_fd fd, bool isnetwork, char const *address) {
+//   com_std_assert(address != NULL);
+//   if (!isnetwork) {
+//     struct sockaddr_un addr = {.sun_family = AF_UNIX};
+//     __builtin_memcpy(&addr.sun_path, address, com_str_ext_len(address));
+//     return connect(fileno(fd), (struct sockaddr *)&addr, sizeof(addr)) == 0;
+//   } else
+//     return NULL;
+// }
+
+void com_std_exit(int32_t status) {
+  (void)status;
+  __asm__ volatile("int $0x21" ::"a"(0x4c00 | (status & 0xff))
+                   : "memory", "cc");
+  __builtin_unreachable();
+}
+
+// void com_std_close(com_std_fd fd) { fclose(fd); }