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7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# Code for the first 2 disk sectors, that all programs in this directory need:
# - load sectors past the first (using BIOS primitives) since only the first is available by default
# - if this fails, print 'D' at top-left of screen and halt
# - initialize a minimal graphics mode
# - switch to 32-bit mode (giving up access to BIOS primitives)
# - set up a handler for keyboard events
# - jump to start of program
#
# To convert to a disk image, first prepare a realistically sized disk image:
# dd if=/dev/zero of=disk.img count=20160 # 512-byte sectors, so 10MB
# Create initial sectors from this file:
# ./bootstrap run apps/hex < baremetal/boot.hex > boot.bin
# Translate other sectors into a file called a.img
# Load all sectors into the disk image:
# cat boot.bin a.img > disk.bin
# dd if=disk.bin of=disk.img conv=notrunc
# To run:
# qemu-system-i386 disk.img
# Or:
# bochs -f apps/boot.bochsrc # boot.bochsrc loads disk.img
#
# Since we start out in 16-bit mode, we need instructions SubX doesn't
# support.
# This file contains just lowercase hex bytes and comments. Zero
# error-checking. Make liberal use of:
# - comments documenting expected offsets
# - size checks on the emitted file (currently: 512 bytes)
# - xxd to eyeball that offsets contain expected bytes
#
# Programs using this initialization:
# - can't use any syscalls
# - can't print text to video memory (past these boot sectors)
7424 - baremetal: downsize graphics resolution If it's large enough that I have doubts whether my top-of-the-line Mac is showing the bottom of the screen inside an emulator, it's too large. This way I also feel more confident that most modern hardware will support this graphics mode, and that these programs will work for others.
2020-12-27 16:33:22 +00:00
# - must only print raw pixels (256 colors) to video memory (resolution 1024x768)
7418 - baremetal: adjust entrypoint address We need a few pages of data for the keyboard mappings. If I moved them to some later address I'd be able to keep the nice round starting address unchanged. But that seems like a superficial aesthetic concern. There's really no value in having an array of hex bytes represented in SubX rather than just raw hex. And it's better to colocate data near the handler code which uses it (and which runs instructions SubX doesn't support).
2020-12-27 06:33:48 +00:00
# - must store their entry-point at address 0x8800
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
## 16-bit entry point
# Upon reset, the IBM PC:
7413
2020-12-27 04:26:11 +00:00
# - loads the first sector (512 bytes)
# from some bootable image (see the boot sector marker at the end of this file)
# to the address range [0x7c00, 0x7e00)
# - starts executing code at address 0x7c00
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# offset 00 (address 0x7c00):
# disable interrupts for this initialization
fa # cli
# initialize segment registers
# this isn't always needed, but the recommendation is to not make assumptions
b8 00 00 # ax <- 0
8e d8 # ds <- ax
8e d0 # ss <- ax
8e c0 # es <- ax
8e e0 # fs <- ax
8e e8 # gs <- ax
# We don't read or write the stack before we get to 32-bit mode. No function
# calls, so we don't need to initialize the stack.
# 0e:
# load second sector from disk
b4 02 # ah <- 2 # read sectors from disk
# dl comes conveniently initialized at boot time with the index of the device being booted
b5 00 # ch <- 0 # cylinder 0
b6 00 # dh <- 0 # track 0
b1 02 # cl <- 2 # second sector, 1-based
7418 - baremetal: adjust entrypoint address We need a few pages of data for the keyboard mappings. If I moved them to some later address I'd be able to keep the nice round starting address unchanged. But that seems like a superficial aesthetic concern. There's really no value in having an array of hex bytes represented in SubX rather than just raw hex. And it's better to colocate data near the handler code which uses it (and which runs instructions SubX doesn't support).
2020-12-27 06:33:48 +00:00
b0 10 # al <- 16 # number of sectors to read; all sectors must be in a single track
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# address to write sectors to = es:bx = 0x7e00, contiguous with boot segment
bb 00 00 # bx <- 0
8e c3 # es <- bx
bb 00 7e # bx <- 0x7e00
cd 13 # int 13h, BIOS disk service
7434 Fix a stale displacement.
2020-12-28 07:01:14 +00:00
0f 82 8a 00 # jump-if-carry disk-error
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# 26:
# undo the A20 hack: https://en.wikipedia.org/wiki/A20_line
# this is from https://github.com/mit-pdos/xv6-public/blob/master/bootasm.S
# seta20.1:
e4 64 # al <- port 0x64
a8 02 # set zf if bit 1 (second-least significant) is not set
75 fa # if zf not set, goto seta20.1 (-6)
b0 d1 # al <- 0xd1
e6 64 # port 0x64 <- al
# 30:
# seta20.2:
e4 64 # al <- port 0x64
a8 02 # set zf if bit 1 (second-least significant) is not set
75 fa # if zf not set, goto seta20.2 (-6)
b0 df # al <- 0xdf
e6 64 # port 0x64 <- al
# 3a:
# adjust video mode
b4 4f # ah <- 4f (VBE)
b0 02 # al <- 02 (set video mode)
7424 - baremetal: downsize graphics resolution If it's large enough that I have doubts whether my top-of-the-line Mac is showing the bottom of the screen inside an emulator, it's too large. This way I also feel more confident that most modern hardware will support this graphics mode, and that these programs will work for others.
2020-12-27 16:33:22 +00:00
bb 05 41 # bx <- 0x0105 (graphics 1024x768x256
7417 - baremetal: drawing on LFB in Bochs
2020-12-27 06:01:45 +00:00
# 0x4000 bit = configure linear frame buffer in Bochs emulator; hopefully this doesn't hurt anything when running natively)
7422
2020-12-27 07:45:37 +00:00
# fallback mode: 0x0101 (640x480x256)
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
cd 10 # int 10h, Vesa BIOS extensions
# 43:
7415 - baremetal: locate the linear frame buffer 0xa0000 only contains a single bank's worth of memory-mapped video RAM. The LFB is supposed to have everything.
2020-12-27 05:21:07 +00:00
# load information for the (hopefully) current video mode
# mostly just for the address to the linear frame buffer
b4 4f # ah <- 4f (VBE)
b0 01 # al <- 01 (get video mode)
7432 Bugfix: 32-bit code in 16-bit mode. Seems like it was benign, maybe.
2020-12-28 06:38:07 +00:00
b9 07 01 # cx <- 0x0107 (mode we requested)
7433 - some major layout changes I'd missed that VBE call 0x4f01 (get video mode) can write up to 256 bytes. Unexpected areas were getting clobbered because I wasn't reserving enough space.
2020-12-28 06:52:39 +00:00
bf 00 7f # di <- 0x7f00 (video mode info)
7415 - baremetal: locate the linear frame buffer 0xa0000 only contains a single bank's worth of memory-mapped video RAM. The LFB is supposed to have everything.
2020-12-27 05:21:07 +00:00
cd 10
7432 Bugfix: 32-bit code in 16-bit mode. Seems like it was benign, maybe.
2020-12-28 06:38:07 +00:00
# 4f:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# switch to 32-bit mode
0f 01 16 # lgdt 00/mod/indirect 010/subop 110/rm/use-disp16
7414
2020-12-27 05:04:46 +00:00
a0 7c # *gdt_descriptor
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
0f 20 c0 # eax <- cr0
66 83 c8 01 # eax <- or 0x1
0f 22 c0 # cr0 <- eax
7414
2020-12-27 05:04:46 +00:00
ea e0 7c 08 00 # far jump to initialize_32bit_mode after setting cs to the record at offset 8 in the gdt (gdt_code)
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# padding
7432 Bugfix: 32-bit code in 16-bit mode. Seems like it was benign, maybe.
2020-12-28 06:38:07 +00:00
# 63:
00 00 00 00 00 00 00 00 00 00 00 00 00
7414
2020-12-27 05:04:46 +00:00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
## GDT: 3 records of 8 bytes each
7414
2020-12-27 05:04:46 +00:00
# 80:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# gdt_start:
# gdt_null: mandatory null descriptor
00 00 00 00 00 00 00 00
# gdt_code: (offset 8 from gdt_start)
ff ff # limit[0:16]
00 00 00 # base[0:24]
9a # 1/present 00/privilege 1/descriptor type = 1001b
# 1/code 0/conforming 1/readable 0/accessed = 1010b
cf # 1/granularity 1/32-bit 0/64-bit-segment 0/AVL = 1100b
# limit[16:20] = 1111b
00 # base[24:32]
# gdt_data: (offset 16 from gdt_start)
ff ff # limit[0:16]
00 00 00 # base[0:24]
92 # 1/present 00/privilege 1/descriptor type = 1001b
# 0/data 0/conforming 1/readable 0/accessed = 0010b
cf # same as gdt_code
00 # base[24:32]
# gdt_end:
# padding
7414
2020-12-27 05:04:46 +00:00
# 98:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
00 00 00 00 00 00 00 00
7414
2020-12-27 05:04:46 +00:00
# a0:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# gdt_descriptor:
17 00 # final index of gdt = gdt_end - gdt_start - 1
7414
2020-12-27 05:04:46 +00:00
80 7c 00 00 # start = gdt_start
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# padding
7414
2020-12-27 05:04:46 +00:00
# a5:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
00 00 00 00 00 00 00 00 00 00
7414
2020-12-27 05:04:46 +00:00
# b0:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# disk_error:
# print 'D' to top-left of screen to indicate disk error
# *0xb8000 <- 0x0f44
# bx <- 0xb800
bb 00 b8
# ds <- bx
8e db # 11b/mod 011b/reg/ds 011b/rm/bx
# al <- 'D'
b0 44
# ah <- 0x0f # white on black
b4 0f
# bx <- 0
bb 00 00
# *ds:bx <- ax
89 07 # 00b/mod/indirect 000b/reg/ax 111b/rm/bx
e9 fb ff # loop forever
# padding
7414
2020-12-27 05:04:46 +00:00
# c1:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
## 32-bit code from this point (still some instructions not in SubX)
7414
2020-12-27 05:04:46 +00:00
# e0:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# initialize_32bit_mode:
66 b8 10 00 # ax <- offset 16 from gdt_start
8e d8 # ds <- ax
8e d0 # ss <- ax
8e c0 # es <- ax
8e e0 # fs <- ax
8e e8 # gs <- ax
# load interrupt handlers
0f 01 1d # lidt 00/mod/indirect 011/subop 101/rm32/use-disp32
7433 - some major layout changes I'd missed that VBE call 0x4f01 (get video mode) can write up to 256 bytes. Unexpected areas were getting clobbered because I wasn't reserving enough space.
2020-12-28 06:52:39 +00:00
f8 7d 00 00 # *idt_descriptor
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# enable keyboard IRQ
b0 fd # al <- 0xfd # enable just IRQ1
e6 21 # port 0x21 <- al
# initialization is done; enable interrupts
fb
7418 - baremetal: adjust entrypoint address We need a few pages of data for the keyboard mappings. If I moved them to some later address I'd be able to keep the nice round starting address unchanged. But that seems like a superficial aesthetic concern. There's really no value in having an array of hex bytes represented in SubX rather than just raw hex. And it's better to colocate data near the handler code which uses it (and which runs instructions SubX doesn't support).
2020-12-27 06:33:48 +00:00
e9 01 0b 00 00 # jump to 0x8800
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# padding
7414
2020-12-27 05:04:46 +00:00
# ff:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
00
# 100:
# null interrupt handler:
cf # iret
# padding
# 101:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# 110:
# keyboard interrupt handler:
# prologue
fa # disable interrupts
60 # push all registers to stack
# acknowledge interrupt
b0 20 # al <- 0x20
e6 20 # port 0x20 <- al
# TODO: perhaps we should check keyboard status
# read keycode into eax
31 c0 # eax <- xor eax; 11/direct 000/r32/eax 000/rm32/eax
e4 60 # al <- port 0x60
7421 - baremetal: beginnings of keyboard map First keypress is detected, but we need to ack it somehow.
2020-12-27 07:38:52 +00:00
# eax <- *(keyboard normal map + eax)
8a # copy m8 at rm32 to r8
80 # 10/*+disp32 000/r8/al 000/rm32/eax
00 80 00 00 # disp32
# store eax in 'keyboard buffer'
7430
2020-12-28 05:09:22 +00:00
89 # copy r32 to rm32
7421 - baremetal: beginnings of keyboard map First keypress is detected, but we need to ack it somehow.
2020-12-27 07:38:52 +00:00
05 # 00/indirect 000/r32/eax 101/rm32/use-disp32
7431 Typo.
2020-12-28 06:33:47 +00:00
30 7d 00 00 # disp32
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# epilogue
61 # pop all registers
fb # enable interrupts
cf # iret
# padding
7421 - baremetal: beginnings of keyboard map First keypress is detected, but we need to ack it somehow.
2020-12-27 07:38:52 +00:00
# 129:
00 00 00 00 00 00 00
# 130:
# keyboard buffer
00 00 00 00
# padding
# 134:
00 00 00 00 00 00 00 00 00 00 00 00
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
7433 - some major layout changes I'd missed that VBE call 0x4f01 (get video mode) can write up to 256 bytes. Unexpected areas were getting clobbered because I wasn't reserving enough space.
2020-12-28 06:52:39 +00:00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
7433 - some major layout changes I'd missed that VBE call 0x4f01 (get video mode) can write up to 256 bytes. Unexpected areas were getting clobbered because I wasn't reserving enough space.
2020-12-28 06:52:39 +00:00
# 1f8:
# idt_descriptor:
ff 00 # idt_end - idt_start - 1
00 7e 00 00 # start = idt_start
# 1fe:
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# final 2 bytes of boot sector
55 aa
## sector 2
# loaded by load_disk, not automatically on boot
# offset 200 (address 0x7e00): interrupt descriptor table
# 32 entries * 8 bytes each = 256 bytes (0x100)
# idt_start:
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
# entry 8: clock
00 7d # target[0:16] = null interrupt handler
08 00 # segment selector (gdt_code)
00 # unused
8e # 1/p 00/dpl 0 1110/type/32-bit-interrupt-gate
00 00 # target[16:32]
# entry 9: keyboard
10 7d # target[0:16] = keyboard interrupt handler
08 00 # segment selector (gdt_code)
00 # unused
8e # 1/p 00/dpl 0 1110/type/32-bit-interrupt-gate
00 00 # target[16:32]
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
# idt_end:
# offset 300 (address 0x7f00):
7433 - some major layout changes I'd missed that VBE call 0x4f01 (get video mode) can write up to 256 bytes. Unexpected areas were getting clobbered because I wasn't reserving enough space.
2020-12-28 06:52:39 +00:00
# video mode info:
00 00 # attributes
00 # winA
00 # winB
# 304
00 00 # granularity
00 00 # winsize
# 308
00 00 # segmentA
00 00 # segmentB
# 30c
00 00 00 00 # realFctPtr (who knows)
# 310
00 00 # pitch
00 00 # Xres
# 314
00 00 # Yres
00 00 # Wchar Ychar
# 318
00 # planes
00 # bpp
00 # banks
00 # memory_model
# 31c
00 # bank_size
00 # image_pages
00 # reserved
# 31f
00 00 # red_mask red_position
00 00 # green_mask green_position
00 00 # blue_mask blue_position
00 00 # rsv_mask rsv_position
00 # directcolor_attributes
# 328
00 00 00 00 # physbase <== linear frame buffer
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
7433 - some major layout changes I'd missed that VBE call 0x4f01 (get video mode) can write up to 256 bytes. Unexpected areas were getting clobbered because I wasn't reserving enough space.
2020-12-28 06:52:39 +00:00
# 32c
# reserved for video mode info
00 00 00 00
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
7418 - baremetal: adjust entrypoint address We need a few pages of data for the keyboard mappings. If I moved them to some later address I'd be able to keep the nice round starting address unchanged. But that seems like a superficial aesthetic concern. There's really no value in having an array of hex bytes represented in SubX rather than just raw hex. And it's better to colocate data near the handler code which uses it (and which runs instructions SubX doesn't support).
2020-12-27 06:33:48 +00:00
# offset 400 (address 0x8000):
# keyboard normal map:
7421 - baremetal: beginnings of keyboard map First keypress is detected, but we need to ack it somehow.
2020-12-27 07:38:52 +00:00
00
# es
1b
# |<--- digits -------------->| - = bs
31 32 33 34 35 36 37 38 39 30 2d 3d 08
# offset 40f
# tb q w e r t y u i o p [ ]
09 71 77 65 72 74 79 75 69 6f 70 5b 5d
# offset 41c
# enter
0a 00
# offset 41e
# a s d f g h j k l ; ' ` \
61 73 64 66 67 68 6a 6b 6c 3b 27 60 00 5c
# offset 42c
# z x c v b n m , . /
7a 78 63 76 62 6e 6d 2c 2e 2f
# offset 436
00 00 00 00 00 00 00 00 00 00
7418 - baremetal: adjust entrypoint address We need a few pages of data for the keyboard mappings. If I moved them to some later address I'd be able to keep the nice round starting address unchanged. But that seems like a superficial aesthetic concern. There's really no value in having an array of hex bytes represented in SubX rather than just raw hex. And it's better to colocate data near the handler code which uses it (and which runs instructions SubX doesn't support).
2020-12-27 06:33:48 +00:00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# 500:
# keyboard shift map:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# 600:
# keyboard ctrl map:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# padding (there might be more keyboard tables)
# 700:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# 800:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# a00:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# offset c00 (address 0x8800)
7404 - baremetal: first example program Design choice: all programs will use a graphics mode (1280x1024) with 256 colors. That should be fairly widely available. (It turns out text modes larger than 80x25 are not widely available even among modern emulators. Mu will need fonts sooner rather than later.) Mu will never try to be smart and do things like autodetect your hardware. We _will_ help you modify Mu for your hardware.
2020-12-26 22:21:04 +00:00
# vim:ft=subx