kvisc/ka/usr/cmd/main.k

; The OS/K Team licenses this file to you under the MIT license.
; See the LICENSE file in the project root for more information.

argbuf.size := 256
argbuf = [argbuf.size]
argv0 = [argbuf.size]
argv1pos = 0

stdin_echoing = 1

prompt = [32]

main:
    mov rsi, prompt
    mov b[rsi+0], 'C'
    mov b[rsi+1], ':'
    mov b[rsi+2], '\'
    mov b[rsi+3], '>'
    mov b[rsi+4], ' '

.print_prompt:
    call print, prompt

    ; empty argbuf
    mov rcx, argbuf.size
    mov rdx, argbuf
    stosb.rep rdx, zero

    ; iterator through argbuf
    mov rcx, zero

    mov q[argv1pos], zero

.input_loop:
    pause
    pause
    pause

    ; Fill .buf with user input
    scan rax
    jmp.axz .input_loop

    ; backspace character?
    b.nz rax, 8, .handle_input

    ; anything to delete?
    jmp.cxz .input_loop     ; no

    ; yes, delete it
    dec rcx, 1
    add rdx, rcx, argbuf
    mov b[rdx], zero

    ; update screen
    cmp b[stdin_echoing], 1
    prn.z 8

    jmp .input_loop

.handle_input:
    cmp b[stdin_echoing], 1
    prn.z rax
    b.z rax, 10, .extract_argv0

    ; when max line length is reached,
    ; force a newline
    b.z rcx, argbuf.size, .extract_argv0

    ; add character to buffer and increase iterator (rcx)
    add rdx, rcx, argbuf
    mov b[rdx], rax
    inc rcx, 1

    ; another one
    jmp .input_loop

.extract_argv0:
    ; did we read anything at all?
    ; if not, just go back to waiting input
    jmp.cxz .print_prompt

    ; find first whitespace or null-terminator
    mov rcx, argbuf.size
    mov rdx, argbuf
    scasb.rep.nz rdx, ' '

    ; argv1 exists? if so, save its position
    mov rsi, rdx

.next_space:
    mov rcx, b[rsi]
    jmp.cxz .do_extract

    ; skip spaces
    cmp rcx, ' '
    inc.z rsi, 1
    jmp.z .next_space

    ; if we're here, we found a
    ; non-zero non-space character
    mov q[argv1pos], rsi

    ; fallthrough

.do_extract:
    ; empty argv0
    mov rcx, argbuf.size
    mov rax, argv0
    stosb.rep rax, zero

    ; how much do we copy?
    sub rcx, rdx, argbuf
    jmp.cxz .detect_builtin
    dec rcx, 1

    mov rdi, argbuf
    mov rsi, argv0

.copy_loop:
    mov b[rsi], b[rdi]

    inc rdi, 1
    inc rsi, 1

    loop .copy_loop

.detect_builtin:

.builtin_cls = "cls"
    call strcmp, argv0, .builtin_cls
    jmp.axz .handle_CLS

.builtin_date = "date"
    call strcmp, argv0, .builtin_date
    jmp.axz .handle_DATE

.builtin_dir = "dir"
    call strcmp, argv0, .builtin_dir
    jmp.axz .handle_DIR

.builtin_dump = "dump"
    call strcmp, argv0, .builtin_dump
    jmp.axz .handle_DUMP

.builtin_echo = "echo"
    call strcmp, argv0, .builtin_echo
    jmp.axz .handle_ECHO

.builtin_exit = "exit"
    call strcmp, argv0, .builtin_exit
    jmp.axz .handle_EXIT

.builtin_help = "help"
    call strcmp, argv0, .builtin_help
    jmp.axz .handle_HELP

.builtin_halt = "halt"
    call strcmp, argv0, .builtin_halt
    jmp.axz .handle_HALT

.builtin_make = "make"
    call strcmp, argv0, .builtin_make
    jmp.axz .handle_MAKE

.builtin_print = "print"
    call strcmp, argv0, .builtin_print
    jmp.axz .handle_PRINT

.builtin_prompt = "prompt"
    call strcmp, argv0, .builtin_prompt
    jmp.axz .handle_PROMPT

.builtin_time = "time"
    call strcmp, argv0, .builtin_time
    jmp.axz .handle_TIME

.builtin_ver = "ver"
    call strcmp, argv0, .builtin_ver
    jmp.axz .handle_VER

    jmp .command_not_found

;
; call builtins
;
.handle_CLS:
    prn PRN_CLEAR
    jmp .print_prompt

.handle_DATE:
    call GetTimeUTC

    push b[rax+3]
    mov rcx, b[rax+4]
    add rcx, rcx, 1
    push rcx
    push w[rax+6]

    call printf, .datefmt
    inc rsp, 40

    jmp .print_prompt

.datefmt = "%d/%d/%d\n"

.handle_DIR:
    call builtins.dir
    jmp .print_prompt

.handle_DUMP:
    dump
    jmp .print_prompt

.handle_ECHO:
    mov rdx, q[argv1pos]
    jmp.dxz .echo.end

    mov rcx, argbuf.size
    prns.rep.nz rdx

.echo.end:
    prn 10
    jmp .print_prompt

.handle_EXIT:
    mov rax, Sys.Shutdown
    trap 0
    jmp .print_prompt

.handle_HALT:
    mov rax, Sys.EnterHaltMode
    trap 0
    jmp .print_prompt

.handle_MAKE:
    mov rax, Sys.CreateFile
    mov ax0, q[argv1pos]
    b.z ax0, zero, .need_params
    trap 0

    b.l rax, zero, .couldnt_open

    jmp .print_prompt

.handle_PRINT:
    mov rax, Sys.OpenFile
    mov ax0, q[argv1pos]
    b.z ax0, zero, .need_params
    trap 0

    b.l rax, zero, .file_not_found

    mov ax0, rax
    mov ax1, FILE_LOADP
    mov ax2, FILE_MAXSZ

    mov rax, Sys.ReadFile
    trap 0

    mov rcx, rax

    mov rax, Sys.CloseFile
    trap 0

    b.l rcx, zero, .couldnt_read
    jmp.cxz .empty_file

    mov rdx, FILE_LOADP
    prns.rep rdx

    jmp .print_prompt

.handle_PROMPT:
    mov ax0, prompt
    mov ax1, q[argv1pos]
    b.z ax1, zero, .need_params
    call strcpy

    jmp .print_prompt

.handle_TIME:
    call GetTimeUTC

    push b[rax]
    push b[rax+1]
    push b[rax+2]
    call printf, .timefmt
    inc rsp, 24

    jmp .print_prompt

.timefmt = "%d:%d:%d\n"

.handle_VER:
    call print, cmd.versionstr
    prn 10

    jmp .print_prompt

.handle_HELP:
    call print, .helpmsg
    call print, .helpmsg.cls
    call print, .helpmsg.date
    call print, .helpmsg.dir
    call print, .helpmsg.dump
    call print, .helpmsg.echo
    call print, .helpmsg.exit
    call print, .helpmsg.help
    call print, .helpmsg.halt
    call print, .helpmsg.make
    call print, .helpmsg.print
    call print, .helpmsg.prompt
    call print, .helpmsg.time
    call print, .helpmsg.ver

    jmp .print_prompt

.helpmsg        = "The following commands are built-in:\n"
.helpmsg.cls    = "    CLS        Clear screen\n"
.helpmsg.date   = "    DATE       Display current date\n"
.helpmsg.dir    = "    DIR        Print contents of current directory\n"
.helpmsg.dump   = "    DUMP       Toggles debug instruction dumping\n"
.helpmsg.echo   = "    ECHO       Write arguments to standard output\n"
.helpmsg.exit   = "    EXIT       Initiate machine shutdown\n"
.helpmsg.help   = "    HELP       Display these messages\n"
.helpmsg.halt   = "    HALT       Put processor in halt mode\n"
.helpmsg.make   = "    MAKE       Create an empty file\n"
.helpmsg.print  = "    PRINT      Display contents of text file\n"
.helpmsg.prompt = "    PROMPT     Change the command line prompt\n"
.helpmsg.time   = "    TIME       Display current time of day\n"
.helpmsg.ver    = "    VER        Display current COMMAND.COM version\n"

.command_not_found:
    call print, argv0
    call print, .cnf_errmsg
    jmp .print_prompt

.cnf_errmsg = ": command not found\n"

.file_not_found:
    push q[argv1pos]
    push argv0
    call printf, .fnf_errmsg
    inc rsp, 16

    jmp .print_prompt

.fnf_errmsg = "%s: %s: file not found\n"

.empty_file:
    push q[argv1pos]
    push argv0
    call printf, .ef_errmsg
    inc rsp, 16

    jmp .print_prompt

.ef_errmsg = "%s: %s: file was empty\n"

.couldnt_open:
    push q[argv1pos]
    push argv0
    call printf, .cno_errmsg
    inc rsp, 16

    jmp .print_prompt

.cno_errmsg = "%s: %s: an error occured while opening file\n"

.couldnt_read:
    push q[argv1pos]
    push argv0
    call printf, .cnr_errmsg
    inc rsp, 16

    jmp .print_prompt

.cnr_errmsg = "%s: %s: an error occured while reading file\n"

.need_params:
    call print, argv0
    call print, .np_errmsg

    jmp .print_prompt

.np_errmsg = ": need more parameters\n"