Write README

README.md

@@ -1,5 +1,36 @@
-- quick drop
-- faster timer
-- fix asm loader
-- document everything
-- prettier pictures
+# TetrOS: bare-metal tetris
+
+## TODO:
+- Fix stage 1 loader
+
+## Features
+- Compiles to a standalone disk image
+- Written from scratch using only Nasm and Rust
+- Custom BIOS bootloader
+- 32-bit x86 OS
+- 🌟 Detailed comments. Read the [makefile](./Makefile), then start in [`./bios/main.asm`](./bios/main.asm).
+
+
+## Non-Features
+- Never tested on real hardware
+- Minimal gameplay and graphics. These features aren't hard to implement, but also don't present any interesting challenges. I have other things to do.
+
+
+## 🚀 Building and Running
+- All scripts are in the [makefile](./Makefile).
+- To build and run, use `make qemu`.
+  - Dependencies: `nasm`, `cargo`, GNU `binutils`, `qemu`
+  - This will NOT work on MacOS. BSD `ld` does not work like GNU `ld`.
+- Alternatively, a compiled disk image for the latest commit is [here](https://git.betalupi.com/api/packages/Mark/generic/tetros/latest/disk.img). This is the same file produced by `make`.
+  - Download it and run `qemu-system-i386 -d cpu_reset -no-reboot -smp 1 -m 2048 -machine q35 -net none -serial stdio -fda "disk.img"`
+
+
+## 📜 Resources
+**Used directly:**
+- [jdh's video](https://www.youtube.com/watch?v=FaILnmUYS_U)
+- [The OSDev wiki](https://wiki.osdev.org/Main_Page)
+- [RedoxOS bootloader](https://gitlab.redox-os.org/redox-os/bootloader)
+
+**Useful background knowledge:**
+- [Writing an OS in Rust](https://os.phil-opp.com)
+- [Operating Systems: From 0 to 1](https://github.com/tuhdo/os01)

bios/cpuid.asm

@@ -1,176 +0,0 @@
-SECTION .text
-USE16
-
-cpuid_required_features:
-    .edx equ cpuid_edx.fpu | cpuid_edx.pse | cpuid_edx.pge | cpuid_edx.fxsr
-    .ecx equ 0
-
-cpuid_check:
-    ; If bit 21 of EFLAGS can be changed, then CPUID is supported
-    pushfd                               ;Save EFLAGS
-    pushfd                               ;Store EFLAGS
-    xor dword [esp],0x00200000           ;Invert the ID bit in stored EFLAGS
-    popfd                                ;Load stored EFLAGS (with ID bit inverted)
-    pushfd                               ;Store EFLAGS again (ID bit may or may not be inverted)
-    pop eax                              ;eax = modified EFLAGS (ID bit may or may not be inverted)
-    xor eax,[esp]                        ;eax = whichever bits were changed
-    popfd                                ;Restore original EFLAGS
-    test eax,0x00200000                  ;eax = zero if ID bit can't be changed, else non-zero
-    jz .no_cpuid
-
-    mov eax, 1
-    cpuid
-
-    and edx, cpuid_required_features.edx
-    cmp edx, cpuid_required_features.edx
-    jne .error
-
-    and ecx, cpuid_required_features.ecx
-    cmp ecx, cpuid_required_features.ecx
-    jne .error
-
-    ret
-
-.no_cpuid:
-    mov si, .msg_cpuid
-    call print
-
-    mov si, .msg_line
-    call print
-
-    jmp .halt
-
-.error:
-    push ecx
-    push edx
-
-    mov si, .msg_features
-    call print
-
-    mov si, .msg_line
-    call print
-
-    mov si, .msg_edx
-    call print
-
-    pop ebx
-    push ebx
-    shr ebx, 16
-    call print_hex
-
-    pop ebx
-    call print_hex
-
-    mov si, .msg_must_contain
-    call print
-
-    mov ebx, cpuid_required_features.edx
-    shr ebx, 16
-    call print_hex
-
-    mov ebx, cpuid_required_features.edx
-    call print_hex
-
-    mov si, .msg_line
-    call print
-
-    mov si, .msg_ecx
-    call print
-
-    pop ebx
-    push ebx
-    shr ebx, 16
-    call print_hex
-
-    pop ebx
-    call print_hex
-
-    mov si, .msg_must_contain
-    call print
-
-    mov ebx, cpuid_required_features.ecx
-    shr ebx, 16
-    call print_hex
-
-    mov ebx, cpuid_required_features.ecx
-    call print_hex
-
-    mov si, .msg_line
-    call print
-
-.halt:
-    cli
-    hlt
-    jmp .halt
-
-.msg_cpuid: db "CPUID not supported",0
-.msg_features: db "Required CPU features are not present",0
-.msg_line: db 13,10,0
-.msg_edx: db "EDX ",0
-.msg_ecx: db "ECX ",0
-.msg_must_contain: db " must contain ",0
-
-cpuid_edx:
-    .fpu                 equ 1 << 0
-    .vme                 equ 1 << 1
-    .de                  equ 1 << 2
-    .pse                 equ 1 << 3
-    .tsc                 equ 1 << 4
-    .msr                 equ 1 << 5
-    .pae                 equ 1 << 6
-    .mce                 equ 1 << 7
-    .cx8                 equ 1 << 8
-    .apic                equ 1 << 9
-    .sep                 equ 1 << 11
-    .mtrr                equ 1 << 12
-    .pge                 equ 1 << 13
-    .mca                 equ 1 << 14
-    .cmov                equ 1 << 15
-    .pat                 equ 1 << 16
-    .pse_36              equ 1 << 17
-    .psn                 equ 1 << 18
-    .clfsh               equ 1 << 19
-    .ds                  equ 1 << 21
-    .acpi                equ 1 << 22
-    .mmx                 equ 1 << 23
-    .fxsr                equ 1 << 24
-    .sse                 equ 1 << 25
-    .sse2                equ 1 << 26
-    .ss                  equ 1 << 27
-    .htt                 equ 1 << 28
-    .tm                  equ 1 << 29
-    .ia64                equ 1 << 30
-    .pbe                 equ 1 << 31
-
-cpuid_ecx:
-    .sse3                equ 1 << 0
-    .pclmulqdq           equ 1 << 1
-    .dtes64              equ 1 << 2
-    .monitor             equ 1 << 3
-    .ds_cpl              equ 1 << 4
-    .vmx                 equ 1 << 5
-    .smx                 equ 1 << 6
-    .est                 equ 1 << 7
-    .tm2                 equ 1 << 8
-    .ssse3               equ 1 << 9
-    .cnxt_id             equ 1 << 10
-    .sdbg                equ 1 << 11
-    .fma                 equ 1 << 12
-    .cmpxchg16b          equ 1 << 13
-    .xtpr                equ 1 << 14
-    .pdcm                equ 1 << 15
-    .pcid                equ 1 << 17
-    .dca                 equ 1 << 18
-    .sse4_1              equ 1 << 19
-    .sse4_2              equ 1 << 20
-    .x2apic              equ 1 << 21
-    .movbe               equ 1 << 22
-    .popcnt              equ 1 << 23
-    .tsc_deadline        equ 1 << 24
-    .aes                 equ 1 << 25
-    .xsave               equ 1 << 26
-    .osxsave             equ 1 << 27
-    .avx                 equ 1 << 28
-    .f16c                equ 1 << 29
-    .rdrand              equ 1 << 30
-    .hypervisor          equ 1 << 31

bios/stage2.asm

@@ -8,10 +8,6 @@ stage2.entry:
     call print_char
     call print_line
 
-
-    ; check for required features
-    call cpuid_check
-
     ; enable A20-Line via IO-Port 92, might not work on all motherboards
     in al, 0x92
     or al, 2
@@ -20,7 +16,6 @@ stage2.entry:
     mov dword [protected_mode.func], stage3.entry
     jmp protected_mode.entry
 
-%include "cpuid.asm"
 %include "gdt.asm"
 %include "protected_mode.asm"
 %include "thunk.asm"

tetros/src/game/falling.rs

@@ -62,6 +62,7 @@ impl Direction {
 		}
 	}
 
+	/*
 	pub fn rot_ccw(self) -> Self {
 		match self {
 			Self::North => Self::West,
@@ -70,6 +71,7 @@ impl Direction {
 			Self::East => Self::North,
 		}
 	}
+	*/
 }
 
 #[derive(Debug, Clone)]
@@ -124,9 +126,11 @@ impl FallingTetromino {
 		self.direction = self.direction.rot_cw()
 	}
 
+	/*
 	pub fn rotate_ccw(&mut self) {
 		self.direction = self.direction.rot_ccw()
 	}
+	*/
 
 	/// Returns the positions of this falling tetromino's tiles.
 	pub fn tiles(&self) -> [(usize, usize); 4] {

tetros/src/lib.rs

@@ -205,12 +205,14 @@ pub unsafe extern "C" fn start(thunk10: extern "C" fn()) -> ! {
 						};
 					}
 
-					Some(InputKey::Down) => {
-						fall_test.rotate_ccw();
+					Some(InputKey::Down) => loop {
+						fall_test.translate(0, 1);
 						if board.tetromino_valid(&fall_test) {
-							fall.rotate_ccw()
-						};
-					}
+							fall.translate(0, 1);
+						} else {
+							break;
+						}
+					},
 
 					Some(InputKey::Left) => {
 						fall_test.translate(-1, 0);
@@ -244,7 +246,7 @@ pub unsafe extern "C" fn start(thunk10: extern "C" fn()) -> ! {
 			board.draw(&mut v, fall.as_ref());
 
 			if let Some(fall_inner) = fall.as_mut() {
-				if t % 5 == 0 {
+				if t % 4 == 0 {
 					let mut fall_test = fall_inner.clone();
 					fall_test.translate(0, 1);
 
@@ -258,7 +260,10 @@ pub unsafe extern "C" fn start(thunk10: extern "C" fn()) -> ! {
 					}
 				}
 			} else {
-				*fall = Some(FallingTetromino::random(5, 1))
+				*fall = Some(FallingTetromino::random(5, 1));
+				if !board.tetromino_valid(fall.as_ref().unwrap()) {
+					panic!("\nGAME OVER");
+				}
 			}
 		})
 	}