Bochs works, failed PIT and beep attempts

Makefile

@@ -30,6 +30,13 @@ clean:
 run: all
 	qemu-system-i386 '$(RUN)$(OUT_EXT)'
 
+bochs: all
+	bochs -qf /dev/null \
+		'ata0-master: type=disk, path="$(RUN)$(OUT_EXT)", mode=flat, cylinders=1, heads=1, spt=1' \
+		'boot: disk' \
+		'display_library: sdl' \
+		'megs: 128'
+
 BIG_IMG_DIR := big_img$(TMP_EXT)
 BOOT_DIR := $(BIG_IMG_DIR)/boot
 GRUB_DIR := $(BOOT_DIR)/grub

README.md

@@ -29,8 +29,11 @@ Hello world programs that run without an operating system.
             1.  [Interrupt zero divide](interrupt_zero_divide.S)
         1.  in
             1.  [in keyboard](in_keyboard.S)
-            1.  [in PIT (TODO)](in_pit.S)
             1.  [in RTC](in_rtc.S)
+            1.  [in PIT (TODO)](in_pit.S)
+            1.  [in beep (TODO)](in_beep.S)
+            1.  [in beep_kernel (TODO)](in_beep_kernel.S)
+            1.  [in beep_illinois (TODO)](in_beep_illinois.S)
             1.  [in mouse (TODO)](in_mouse.S)
     1.  APM
         1.  [APM shutdown](apm_shutdown.S)
@@ -52,7 +55,7 @@ Hello world programs that run without an operating system.
 
 ## Getting started
 
-    sudo apt-get install build-essential gnu-efi qemu nasm xorriso
+    sudo apt-get install bochs bochs-sdl build-essential gnu-efi qemu nasm xorriso
 
 ### Emulator
 
@@ -65,6 +68,10 @@ Run a given program:
     make run RUN=min
     make run RUN=bios_one_char
 
+Use Bochs instead of QEMU:
+
+    make bochs RUN=min
+
 Tested on Ubuntu 14.04 AMD64.
 
 ### Real hardware

TODO.md

@@ -8,7 +8,20 @@
 -   instructions
 
     - cache: wbinvd
-    - outb inb
+
+    -   inb outb
+
+        Answer with bare metal Tetris
+
+        - http://stackoverflow.com/questions/8365746/what-does-outb-in-att-asm-mean
+        - http://stackoverflow.com/questions/3215878/what-are-in-out-instructions-in-x86-used-for
+        - http://wiki.osdev.org/Text_UI
+
+        Port 0x80 on Linux kenrnel: https://github.com/torvalds/linux/blob/v4.2/arch/x86/boot/boot.h#L78 http://stackoverflow.com/questions/6793899/what-does-the-0x80-port-address-connects
+
+        Port 0x61 speaker https://courses.engr.illinois.edu/ece390/books/labmanual/io-devices-speaker.html
+
+    - http://wiki.osdev.org/GUI
     - lgdtl, paging http://stackoverflow.com/questions/21128311/the-physical-address-of-global-descriptor-table http://stackoverflow.com/questions/7415515/problem-accessing-control-registers-cr0-cr2-cr3
     - lidtl, interrupts, IDTR
         - https://en.wikipedia.org/wiki/Double_fault
@@ -62,7 +75,7 @@
 
 -   play with hardware
 
-    -   keyboard through interrupt (high level int 16 bios done)
+    -   keyboard through interrupt (high level BIOS int 16 that waits for input done)
         - keyboard protected mode: http://stackoverflow.com/questions/219120/x86-assembly-protected-mode-keyboard-access
     -   set a pixel on screen in protected mode http://stackoverflow.com/questions/14419088/assembly-draw-a-pixel-on-the-screen-in-protected-mode
     -   USB

bibliography.md

@@ -22,6 +22,8 @@
 
 -   <https://github.com/scanlime/metalkit> A more automated / general bare metal compilation system. Untested, but looks promising.
 
+-   <https://courses.engr.illinois.edu/ece390/books/labmanual/index.html> Illinois course from 2004
+
 The following did not work on my machine out of the box:
 
 - <https://github.com/apparentlymart/ToyOS>

common.h

@@ -44,6 +44,8 @@ Print a single immediate byte or 8 bit register.
 Usage: character 'A' (ASCII 61):
 
     PUTS(61)
+
+Clobbers: ax
 */
 #define PUTC(c) \
     mov $0x0E, %ah;\
@@ -54,21 +56,23 @@ Usage: character 'A' (ASCII 61):
 Convert a byte to hex ASCII value.
 c: r/m8 byte to be converted
 Output: two ASCII characters, is stored in `al:bl`
+Clobbers: ax
 http://stackoverflow.com/questions/3853730/printing-hexadecimal-digits-with-assembly
 */
 #define HEX(c) GAS_HEX c
 .macro GAS_HEX c
     mov \c, %al
-    mov \c, %bl
+    mov \c, %ah
     shr $4, %al
     GAS_HEX_NIBBLE al
-    and $0x0F, %bl
-    GAS_HEX_NIBBLE bl
+    and $0x0F, %ah
+    GAS_HEX_NIBBLE ah
 .endm
 
 /*
 Convert the low nibble of a r8 reg to ASCII of 8-bit in-place.
 reg: r8 to be converted
+Clobbered registers: none
 Output: stored in reg itself. Letters are uppercase.
 */
 .macro GAS_HEX_NIBBLE reg
@@ -84,10 +88,16 @@ letter:
 end:
 .endm
 
+/*
+Print a byte as two hexadecimal digits.
+
+Clobbers: ax, dl
+*/
 #define PRINT_HEX(reg) \
     HEX(<reg>);\
+    mov %ah, %dl;\
     PUTC(%al);\
-    PUTC(%bl)
+    PUTC(%dl)
 
 #define PRINT_NEWLINE \
     PUTC($0x0A);\

in.md

@@ -1,8 +1,16 @@
 # in
 
+# out
+
+IO operations.
+
+Do not work with immediates: only registers or memory locations.
+
+## Bit 0x80
+
 TODO http://wiki.osdev.org/CMOS#Getting_Current_Date_and_Time_from_RTC says:
 
     /* since the 0x80 bit of al is not set, NMI is active */
-    out 0x70,al
+    out 0x70, al
 
 What does it mean?

in_beep.S

@@ -0,0 +1,27 @@
+/*
+The beep circuit is linked to the PIT.
+
+I think it is possible to make a beep after a certain amount of time passes.
+
+http://fly.srk.fer.hr/GDM/articles/sndmus/speaker1.html
+*/
+
+#include "common.h"
+
+.equ div, 1193181 / 1000;
+
+BEGIN
+start:
+    PUTC($0x61)
+    mov $0xb6, %al
+    out %al, $0x43    /* Ctr 2, squarewave, load, binary */
+    mov div, %al
+    out %al, $0x42    /* LSB of counter */
+    mov div, %al
+    shr $8, %al
+    out %al, $0x42    /* MSB of counter */
+    in $0x61, %al         /* Dummy read of System Control Port B */
+    mov $0x03, %al
+    out %al, $0x61    /* Enable timer 2 output to speaker */
+    jmp start
+END

in_beep_illinois.S

@@ -0,0 +1,37 @@
+/*
+https://courses.engr.illinois.edu/ece390/books/labmanual/io-devices-speaker.html
+
+TODO not working on QEMU
+*/
+
+#include "common.h"
+BEGIN
+start:
+    PUTC($0x61)
+
+    movb    $182,%al        # Prepare the speaker for the
+    outb    %al, $0x43       #  note.
+    movw    $4560,%ax       # Frequency number (in decimal)
+                            #  for middle C.
+    outb    %al, $0x42       # Output low byte.
+    movb    %ah,%al         # Output high byte.
+    outb    %al, $0x42
+    inb     $0x61,%al       # Turn on note (get value from
+                            #  port 61h).
+    orb     $0b00000011,%al # Set bits 1 and 0.
+    outb    %al, $0x61       # Send new value.
+    movw    $25,%bx         # Pause for duration of note.
+.pause1:
+    movw    $65535,%cx
+.pause2:
+    decw    %cx
+    jne     .pause2
+    decw    %bx
+    jne     .pause1
+    inb     $0x61,%al       # Turn off note (get value from
+                            #  port 61h).
+    andb    $0b11111100,%al # Reset bits 1 and 0.
+    outb    %al, $0x61       # Send new value.
+
+    jmp start
+END

in_beep_kernel.S

@@ -0,0 +1,25 @@
+/*
+Extracted from: https://github.com/torvalds/linux/blob/v4.2/arch/x86/realmode/rm/wakemain.c#L38
+
+TODO not working on QEMU
+*/
+
+#include "common.h"
+
+.equ div, 1193181 / 1000;
+
+BEGIN
+start:
+    PUTC($0x61)
+    mov $0xb6, %al
+    out %al, $0x43    /* Ctr 2, squarewave, load, binary */
+    mov div, %al
+    out %al, $0x42    /* LSB of counter */
+    mov div, %al
+    shr $8, %al
+    out %al, $0x42    /* MSB of counter */
+    in $0x61, %al         /* Dummy read of System Control Port B */
+    mov $0x03, %al
+    out %al, $0x61    /* Enable timer 2 output to speaker */
+    jmp start
+END

in_pit.S

@@ -1,10 +1,46 @@
 /*
-TODO http://wiki.osdev.org/PIT
+# PIT
+
+TODO get working
+
+TODO answer with example http://stackoverflow.com/questions/13950264/does-using-tsc-as-clock-source-improve-timer-and-scheduling-granularity
+
+Programmable interrupt timer.
+
+Can generate periodic interrupts, or sounds.
+
+The kernel has a Morse code encoder with it. https://github.com/torvalds/linux/blob/v4.2/arch/x86/realmode/rm/wakemain.c#L38
 
 Going to use in 0x40
+
+## 1193181
+
+Magic number that is the frequency of the oscillator.
+
+http://f.osdev.org/viewtopic.php?f=1&t=15503
+
+## Bibliography
+
+- https://en.wikipedia.org/wiki/Intel_8253
+- http://wiki.osdev.org/PIT
+- http://kernelx.weebly.com/programmable-interval-timer.html
 */
 
 #include "common.h"
+
+#define PIT_CHANNEL0 $0x40
+#define PIT_CHANNEL1 $0x41
+#define PIT_CHANNEL2 $0x42
+#define PIT_CMDREG $0x43
+
 BEGIN
-hlt
+start:
+    #u16 div = 1193181/hz;
+    # Linux kernel
+    #outb(0xb6, 0x43);    /* Ctr 2, squarewave, load, binary */
+    #outb(div, 0x42);    /* LSB of counter */
+    #outb(div >> 8, 0x42);    /* MSB of counter */
+    #enable = 0x03;        /* Turn on speaker */
+    #inb(0x61);        /* Dummy read of System Control Port B */
+    #outb(enable, 0x61);    /* Enable timer 2 output to speaker */
 END

in_rtc.S

@@ -1,14 +1,35 @@
 /*
-TODO http://wiki.osdev.org/RTC
+# in RTC
+
+Real time clock.
+
+Gives wall time with precision of seconds.
+
+Uses a separate battery to keep going.
+
+http://stackoverflow.com/questions/1465927/how-can-i-access-system-time-using-nasm
+
+http://wiki.osdev.org/RTC
+
+http://wiki.osdev.org/CMOS
 
 Kenrel 4.2 usage: https://github.com/torvalds/linux/blob/v4.2/arch/x86/kernel/rtc.c#L121
 
-http://stackoverflow.com/questions/1465927/how-can-i-access-system-time-using-nasm
+## Milliseconds
+
+Not possible. Must use the PIT.
+
+## Time zone
+
+QEMU uses UTC.
 */
 
 #include "common.h"
 BEGIN
 
+/*
+TODO what do those numbers mean? Where is this all documented?
+*/
 .equ RTCaddress, 0x70
 .equ RTCdata, 0x71
 
@@ -68,6 +89,4 @@ update_in_progress:
     PRINT_NEWLINE
 
     jmp update_in_progress
-
-hlt
 END

nasm/bios_one_char.asm

@@ -0,0 +1,8 @@
+org 0x7c00
+bits 16
+cli
+mov ax, 0x0E61
+int 0x10
+hlt
+times 510 - ($-$$) db 0
+dw 0xaa55