freeze dos progress, maybe some day

.gitignore

@@ -3,8 +3,11 @@
 **/*.EXE
 **/*.exe
 **/*.out
+**/*.elf
+**/*.bin
 **/*.BAK
 **/*.wdl
+**/*.DX
 *.sublime-*
 
 Player/player

Common/cfg.h

@@ -2,6 +2,8 @@
     Configuration file.
 */
 
+/* TODO: Move to root or Shared/ folder? */
+
 #ifndef COM_CFG_H
 #define COM_CFG_H
 

Player/Display/dos.c

@@ -1,17 +1,16 @@
 #include "display.h"
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
-#include <string.h>
 
-#define WIDTH 640
+#define WIDTH 320
-#define HEIGHT 480
+#define HEIGHT 200
 #define MODE_VGA_320_200_8 0x13
 #define MODE_VESA_640_480_8 0x101
 
-/*
+/* https://www.phatcode.net/res/262/files/dpmi09.html */
-  TODO: https://github.com/depp/elf2dos/blob/master/elf/elf.go
+/* http://www.techhelpmanual.com/27-dos__bios___extensions_service_index.html */
-        https://www.edm2.com/index.php/LX_-_Linear_eXecutable_Module_Format_Description
-  Do not use anything but Clang in the end.
-  */
 
 // 8-color VGA palette gradient, lighter shades of lavender to pink
 #define COLOR_OFFSET 0x50
@@ -132,13 +131,183 @@
 //   return NULL;
 // }
 
+/* Not really needed i guess? */
+// static inline bool real_mode_interrupt(uint8_t interrupt) {
+//   bool carry_clear;
+//   __asm__ volatile("int $0x31"
+//                    : "=@ccnc"(carry_clear)
+//                    : "a"(0x0300), "b"(interrupt), "c"(0), "D"(&dpmi_regs)
+//                    : "memory", "cc");
+//   return !carry_clear;
+// }
+
+typedef struct {
+  uint16_t rm_segment;
+  uint16_t pm_selector;
+} LowMemBlock;
+
+// Allocates low memory under 1MB
+static inline LowMemBlock allocate_low_mem(uint32_t size_in_bytes) {
+  LowMemBlock block = {0, 0};
+  uint32_t paragraphs =
+      (size_in_bytes + 15) >> 4; // Convert bytes to paragraphs
+
+  uint16_t seg, sel;
+  uint8_t failed = 0;
+
+  __asm__ __volatile__(
+      "movw $0x0100, %%ax \n\t" // DPMI allocate DOS memory block
+      "int $0x31          \n\t"
+      "setc %2            \n\t" // Check Carry Flag for error
+      : "=a"(seg), "=d"(sel), "=r"(failed)
+      : "b"(paragraphs)
+      : "cc");
+
+  if (!failed) {
+    block.rm_segment = seg;
+    block.pm_selector = sel;
+  }
+  return block;
+}
+
+static inline void copy_to_low_mem(LowMemBlock block, char *data,
+                                   uint32_t size) {
+  __asm__ volatile("movw %0, %%es\n"
+                   "movw %1, %%di\n"
+                   "movw %2, %%si\n"
+                   "movw .data, %%ax\n"
+                   "movw %3, %%cx\n"
+                   "cld\n"
+                   "rep movsb" ::"r"(block.rm_segment),
+                   "r"(block.pm_selector), "r"(data), "r"(size)
+                   : "memory", "cc", "ax", "bx", "cx", "esi", "di");
+}
+
+// Frees the allocated low memory (DPMI Ax=0101h)
+static inline void free_low_mem(uint16_t selector) {
+  __asm__ __volatile__("movw $0x0101, %%ax \n\t" // DPMI free DOS memory block
+                       "int $0x31"
+                       :
+                       : "d"(selector)
+                       : "ax", "cc");
+}
+
+static inline void set_video_mode(uint16_t mode) {
+  __asm__ volatile("int $0x10" : : "a"(mode) : "memory", "cc");
+}
+
+/* http://www.techhelpmanual.com/439-dos_fn_40h__write_to_file_via_handle.html
+ */
+static inline void writetest(void) {
+  __asm__ volatile("int $0x21" : : "a"(0x0200), "d"('Y') : "memory", "cc");
+}
+
+/* http://www.techhelpmanual.com/630-int_31h_0800h__physical_address_mapping.html
+ */
+static inline void *map_physical_address(uint32_t physical_addr,
+                                         uint32_t size) {
+  uint16_t high, low;
+  bool carry_clear;
+  __asm__ volatile("int $0x31"
+                   : "=b"(high), "=c"(low), "=@ccnc"(carry_clear)
+                   : "a"(0x0800), "b"(physical_addr >> 16),
+                     "c"(physical_addr & 0xFFFF), "S"(size >> 16),
+                     "D"(size & 0xFFFF)
+                   : "memory", "cc");
+  return !carry_clear ? NULL : (void *)(intptr_t)((high << 16) | low);
+}
+
+static inline uint16_t alloc_ldt_descriptor(void) {
+  bool carry_clear;
+  uint16_t selector;
+  __asm__ volatile("int $0x31"
+                   : "=a"(selector), "=@ccnc"(carry_clear)
+                   : "a"(0x0000), "c"(1)
+                   : "memory", "cc");
+  return !carry_clear ? selector : 0;
+}
+
+static inline bool set_segment_base_address(uint16_t selector,
+                                            uint32_t baseaddr) {
+  bool carry_clear;
+  __asm__ volatile("int $0x31"
+                   : "=a"(selector), "=@ccnc"(carry_clear)
+                   : "a"(0x0007), "c"(baseaddr >> 16), "d"(baseaddr & 0xFFFF)
+                   : "memory", "cc");
+  return !carry_clear;
+}
+
+static inline bool set_segment_limit(uint16_t selector, uint32_t size) {
+  bool carry_clear;
+  __asm__ volatile("int $0x31"
+                   : "=@ccnc"(carry_clear)
+                   : "a"(0x0008), "b"(selector), "c"(size >> 16),
+                     "d"(size & 0xFFFF)
+                   : "memory", "cc");
+  return !carry_clear;
+}
+
+static inline bool set_segment_rights(uint16_t selector, bool read,
+                                      bool write) {
+  bool carry_clear;
+  uint16_t flags =
+      1 | (write << 1) | (1 << 4) | (1 << 7) | (1 << 14) | (1 << 15);
+  __asm__ volatile("int $0x31"
+                   : "=@ccnc"(carry_clear)
+                   : "a"(0x0009), "b"(selector), "c"(flags)
+                   : "memory", "cc");
+  return !carry_clear;
+}
+
+static inline void use_segment(uint16_t selector) {
+  __asm__ volatile("" : "=S"(selector)::);
+}
+
+/* https://tippach.hier-im-netz.de/wdosx/int21api.html#f09 */
+static inline void print_to_console(char *const str) {
+  __asm__ volatile("int $0x21" ::"a"(0x0900), "d"(str)
+                   : "memory", "cc", "esi", "edi", "esp");
+}
+
+static uint32_t test = 0x1420124;
+
 // extern int plr_display_dos_main(int argc, char *argv[]) {
 extern int plr_display_dos_main(void) {
-  char *buf = (char *)0xA0000; // VGA memory address
+  print_to_console("Fuck you stupid shit");
+  return -1;
+
+  uint16_t base = alloc_ldt_descriptor();
+  if (!base) {
+    print_to_console("Cannot allocate LDT descriptor");
+    return -1;
+  }
+
+  if (!set_segment_base_address(base, 0xA0000)) {
+    print_to_console("Cannot set LDT base address");
+    return -1;
+  }
+
+  if (!set_segment_limit(base, 0x10000)) {
+    print_to_console("Cannot set LDT limit");
+    return -1;
+  }
+
+  use_segment(base);
+
+  // char *volatile buf = (void *)(intptr_t)0xA0000; // VGA memory address
+  // char *buf = map_physical_address(0xA0000, 0x10000); // VGA memory
+  char *buf = map_physical_address(0xA0000, 0x10000); // VGA memory
+  // address
+  if (!buf)
+    return -1;
   int x, y;
 
+  // if (!buf)
+  //   return -1;
+
   // unsigned char saved_mode = get_video_mode(); // Save original mode
-  // set_vesa_video_mode(MODE_VESA_640_480_8);    // Set our VGA mode
+  // set_vesa_video_mode(MODE_VESA_640_480_8); // Set our VGA mode
+  set_video_mode(MODE_VGA_320_200_8); // Set our VGA mode
 
   // buf = find_display_memory();
 
@@ -162,9 +331,25 @@ extern int plr_display_dos_main(void) {
     for (y = 0; y < HEIGHT; y++) {
       for (x = 0; x < WIDTH; x++) {
         buf[y * WIDTH + x] = COLOR_OFFSET + y / COLOR_STEP;
+        // __asm__ volatile("int $0x10"
+        //                  :
+        //                  : "a"(0x0C << 8 | COLOR_OFFSET + y / COLOR_STEP),
+        //                    "b"(0), "c"(x), "d"(y)
+        //                  : "memory", "cc");
       }
     }
+    // writetest();
+    __asm__ volatile("int $0x16" : : "a"(0x00) : "memory", "cc");
   }
 
+  // dpmi_regs = (struct dpmi_regs){.eax = 0x00004C00};
+  // __asm__ volatile("movw $0x0300, %%ax\n"
+  //                  "movb $0x21, %%bl\n"
+  //                  "xorb %%bh, %%bh\n"
+  //                  "xorw %%cx, %%cx\n"
+  //                  "movl $dpmi_regs, %%edi\n"
+  //                  "int $0x31" ::
+  //                      : "memory", "cc", "ax", "bx", "cx", "edi");
+
   return 0;
 }

Player/Main/dos.s

@@ -1,47 +1,18 @@
 .section .data
     .align 4
+# TODO: Make sure it's placed under 1 MiB.
 # The DPMI Register Structure (50 bytes total)
 # This holds the register states injected into Real Mode.
-dpmi_regs:
-    .long 0         # edi  (offset 0)
-    .long 0         # esi  (offset 4)
-    .long 0         # ebp  (offset 8)
-    .long 0         # esp / reserved (offset 12)
-    .long 0         # ebx  (offset 16)
-    .long 0         # edx  (offset 20)
-    .long 0         # ecx  (offset 24)
-dpmi_eax:
-    .long 0         # eax  (offset 28)
-    .short 0        # flags(offset 32)
-    .short 0        # es   (offset 34)
-    .short 0        # ds   (offset 36)
-    .short 0        # fs   (offset 38)
-    .short 0        # gs   (offset 40)
-    .short 0        # ip   (offset 42)
-    .short 0        # cs   (offset 44)
-    .short 0        # sp   (offset 46)
-    .short 0        # ss   (offset 48)
 
 .section .text
 .global _start
 
 _start:
+    push %ebp
+    mov %esp, %ebp
+    cld
+
     call plr_display_dos_main
 
-    # 1. Set up the Real-Mode registers inside the DPMI structure
+    movb $0x4C, %ah
-    # AH = 4Ch (DOS Exit Function), AL = 00h (Return Code 0)
+    int $0x21
-    movl $0x00004C00, dpmi_eax
-
-    # 2. Call DPMI Simulate Real Mode Interrupt
-    movw $0x0300, %ax    # DPMI Function: Simulate Real Mode Interrupt
-    movb $0x21, %bl      # Interrupt number to trigger (INT 21h)
-    movb $0x00, %bh      # Flags (Must be 0)
-    movw $0x0000, %cx    # Number of words to copy to RM stack (0)
-    
-    # ES:EDI points to our DPMI register block. 
-    # In WDOSX flat model, %es already targets the flat data descriptor.
-    movl $dpmi_regs, %edi
-    
-    int $0x31            # Trigger DPMI host to execute the RM interrupt
-
-    # --- Execution halts here as DOS terminates the program ---

Player/Makefile

@@ -3,6 +3,7 @@ RELEASE ?= 0 # Optimize.
 DEBUG 	?= 1 # Emit debug info.
 SQUEEZE ?= 0 # Nuclear option to save space.
 BITS 	?= 64
+RUN 	?= 0
 CFLAGS = -Wall -std=gnu99 -flto=thin -ffast-math -fno-ident -fvisibility=hidden -fuse-ld=lld
 ifeq ($(MAKECMDGOALS),linux)
 	CFLAGS += -fno-pic -fno-pie
@@ -64,13 +65,19 @@ wasm:
 	$(CC) -o player.wasm $(WASM) $(CFLAGS)
 
 # https://tippach.hier-im-netz.de/wdosx
-dos: CFLAGS += -ffreestanding -m32 -fno-PIC -fno-PIE -no-pie -nostdlib -nodefaultlibs
+dos: CFLAGS += -ffreestanding -m32 -fno-PIC -fno-PIE -nostdlib -nodefaultlibs
 dos: 
-	$(CC) -c ./Main/dos.s -o ./Main/dos.o $(CFLAGS)
+	$(CC) -c ./Main/dos.s -o ./Main/dos.o -m32
 	$(CC) -c ./Display/dos.c -o ./Display/dos.o $(CFLAGS)
-	ld.lld -m elf_i386 --oformat binary -Ttext 0x0 --image-base=0x0 ./Main/dos.o ./Display/dos.o -o dos.bin
+	ld.lld -m elf_i386 -T dos.ld ./Main/dos.o ./Display/dos.o -o dos.elf
-	dosbox -noconsole -c "mount c $(PWD)" -c "c:" -c "WDOSX\STUBIT.EXE DOS.BIN" -exit
+	objcopy -O binary --strip-all dos.elf dos.bin
-	mv ./DOS.BIN ./DOS.EXE
+	cat WDosX/WDOSX.DX dos.bin > DOS.EXE
-
+ifeq ($(RUN), 1)
+ifeq ($(DEBUG), 1)
+	dosbox -c "mount c $(PWD)" -c "c:" -c "WDOSX\WUDEBUG.EXE DOS.EXE"
+else 
+	dosbox -c "mount c $(PWD)" -c "c:" -c "DOS.EXE"
+endif
+endif
 clean:
 	rm -r *.o ../*.o

Player/dos.ld

@@ -0,0 +1,41 @@
+SECTIONS
+{
+  . = 0x00000;
+
+  /* TODO: Make sure WDOSX.DX is placed first, before .text */
+  textstart = .;
+  .text ALIGN(16) : {
+    *(.text*)
+  }
+  textend = .;
+
+  /* We will need to manually map this. */
+  /* At runtime we can figure this out from mapped code segment. */
+  datastart = .;
+  .rodata : {
+    *(.rodata*)
+  }
+
+  .data : {
+    *(.data*)
+  }
+  dataend = .;
+
+  /* TODO: We need to manually map this, as loader is incapable of doing so with flat binary. */
+  bssstart = .;
+  .bss : {
+    *(.bss*)
+    *(COMMON)
+  }
+  bssend = .;
+
+  /* Will be discarded with objcopy. */
+  .shstrtab : {
+    *(.shstrtab*)
+  }
+
+  /* Discard bloat and unnecessary ELF sections */
+  /DISCARD/ : {
+    *(*)
+  }
+}