240 lines
4.3 KiB
Plaintext
240 lines
4.3 KiB
Plaintext
; The OS/K Team licenses this file to you under the MIT license.
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; See the LICENSE file in the project root for more information.
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argbuf.size := 256
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argbuf = [argbuf.size]
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argv0 = [argbuf.size]
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argv1pos = 0
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stdin_echoing = 1
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ps1 = "C:\\> "
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main:
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.print_prompt:
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mov rcx, STRLEN_MAX
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mov rdx, ps1
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prns.rep.nz rdx
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; empty argbuf
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mov rcx, argbuf.size
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mov rdx, argbuf
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stosb.rep rdx, 0
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; iterator through argbuf
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xor rcx, rcx
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.input_loop:
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pause
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pause
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; Fill .buf with user input
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scan rax
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b.z rax, 0, .input_loop
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; backspace character?
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b.nz rax, 8, .handle_input
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; anything to delete?
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b.z rcx, 0, .input_loop
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; delete it
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dec rcx
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add rdx, rcx, argbuf
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mov b[rdx], 0
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; update screen
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cmp b[stdin_echoing], 1
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prn.z 8
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jmp .input_loop
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.handle_input:
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cmp b[stdin_echoing], 1
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prn.z rax
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b.z rax, 10, .extract_argv0
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; when max line length is reached,
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; force a newline
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b.z rcx, argbuf.size, .extract_argv0
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; add character to buffer and increase iterator (rcx)
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add rdx, rcx, argbuf
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mov b[rdx], rax
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inc rcx
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; another one
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jmp .input_loop
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.extract_argv0:
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; did we read anything at all?
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; if not, just go back to waiting input
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b.z rcx, 0, .print_prompt
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; find first whitespace or null-terminator
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mov rcx, argbuf.size
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mov rdx, argbuf
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scasb.rep.nz rdx, ' '
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; argv1 exists? if so, save its position
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mov r11, rdx
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b.z b[r11], 0, .no_argv1
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inc r11
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.next_space:
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mov rx8, b[r11]
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b.z rx8, 0, .no_argv1
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; skip spaces
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cmp rx8, ' '
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inc.z r11
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jmp.z .next_space
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mov q[argv1pos], r11
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; fallthrough
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.no_argv1:
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; empty argv0
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mov rcx, argbuf.size
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mov rax, argv0
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stosb.rep rax, 0
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; extract argv0
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sub rcx, rdx, argbuf
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mov rdx, argbuf
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mov rax, argv0
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movsb.rep rax, rdx
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.detect_builtin:
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.builtin_cls = "cls"
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mov ax0, argv0
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mov ax1, .builtin_cls
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call strcmp
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b.z rax, 0, .handle_CLS
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.builtin_dir = "dir"
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mov ax0, argv0
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mov ax1, .builtin_dir
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call strcmp
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b.z rax, 0, .handle_DIR
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.builtin_echo = "echo"
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mov ax0, argv0
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mov ax1, .builtin_echo
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call strcmp
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b.z rax, 0, .handle_ECHO
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.builtin_exit = "exit"
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mov ax0, argv0
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mov ax1, .builtin_exit
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call strcmp
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b.z rax, 0, .handle_EXIT
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.builtin_help = "help"
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mov ax0, argv0
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mov ax1, .builtin_help
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call strcmp
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b.z rax, 0, .handle_HELP
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.builtin_print = "print"
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mov ax0, argv0
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mov ax1, .builtin_print
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call strcmp
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b.z rax, 0, .handle_PRINT
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.builtin_ver = "ver"
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mov ax0, argv0
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mov ax1, .builtin_ver
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call strcmp
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b.z rax, 0, .handle_VER
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; fallthrough
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.exec_prog:
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; fallthrough
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.not_found:
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mov rcx, STRLEN_MAX
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mov rdx, argv0
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prns.rep.nz rdx
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mov rdx, .errmsg
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prns.rep.nz rdx
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jmp .print_prompt
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.errmsg = " : command not found\n"
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;
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; call builtins
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;
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.handle_CLS:
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prn 0xC15000AF
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jmp .print_prompt
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.handle_DIR:
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call builtins.dir
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jmp .print_prompt
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.handle_ECHO:
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mov rdx, q[argv1pos]
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b.z rdx, 0, .echo.end
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mov rcx, argbuf.size
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prns.rep.nz rdx
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.echo.end:
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prn 10
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jmp .print_prompt
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.handle_EXIT:
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mov rax, Sys.Shutdown
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trap 0
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.handle_PRINT:
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jmp .print_prompt
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.handle_VER:
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mov rcx, STRLEN_MAX
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mov rdx, cmd.versionstr
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prns.rep.nz rdx
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prn 10
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jmp .print_prompt
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.handle_HELP:
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mov rcx, STRLEN_MAX
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mov rdx, .helpmsg
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prns.rep.nz rdx
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mov rdx, .helpmsg.cls
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prns.rep.nz rdx
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mov rdx, .helpmsg.dir
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prns.rep.nz rdx
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mov rdx, .helpmsg.echo
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prns.rep.nz rdx
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mov rdx, .helpmsg.exit
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prns.rep.nz rdx
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mov rdx, .helpmsg.help
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prns.rep.nz rdx
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mov rdx, .helpmsg.print
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prns.rep.nz rdx
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mov rdx, .helpmsg.ver
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prns.rep.nz rdx
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jmp .print_prompt
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.helpmsg = "The following commands are built-in:\n"
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.helpmsg.cls = " CLS Clear screen\n"
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.helpmsg.dir = " DIR Print contents of current directory\n"
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.helpmsg.echo = " ECHO Write arguments to standard output\n"
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.helpmsg.exit = " EXIT Initiate machine shutdown\n"
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.helpmsg.help = " HELP Show these messages\n"
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.helpmsg.print = " PRINT Show contents of text file\n"
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.helpmsg.ver = " VER Show current COMMAND.COM and DOS kernel versions\n"
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