;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;                                                                          ;;
;; This file is part of 'M', a MIPS system emulator.                        ;;
;;                                                                          ;;
;; (C) 2019 Stanislav Datskovskiy ( www.loper-os.org )                      ;;
;; http://wot.deedbot.org/17215D118B7239507FAFED98B98228A001ABFFC7.html     ;;
;;                                                                          ;;
;; You do not have, nor can you ever acquire the right to use, copy or      ;;
;; distribute this software ; Should you use this software for any purpose, ;;
;; or copy and distribute it to anyone or in any manner, you are breaking   ;;
;; the laws of whatever soi-disant jurisdiction, and you promise to         ;;
;; continue doing so for the indefinite future. In any case, please         ;;
;; always : read and understand any software ; verify any PGP signatures    ;;
;; that you use - for any purpose.                                          ;;
;;                                                                          ;;
;; See also http://trilema.com/2015/a-new-software-licensing-paradigm .     ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


;-----------------------------------------------------------------------------
;; State
;-----------------------------------------------------------------------------
section .bss
        tty             resb TTY_Config_size  ; Linux tty state
        IOBUF           resb 1                ; I/O buffer for print
;-----------------------------------------------------------------------------

;----------------------------------------------------------------------------
;; TTY State Storage
struc   TTY_Config
        ;; Shell's old tty config (restore on quit) :
        .old_tty        resb    12
        .old_lflag      resb     4
        .old_brest      resb    44
        ;; Modified tty config (to run with) :
        .tty            resb    12
        .lflag          resb     4
        .brest          resb    44
endstruc
;----------------------------------------------------------------------------

section .text

;-----------------------------------------------------------------------------
_Cure_TTY:
        ;; Get initial tty state (for restore after quit) :
        mov     rdx, tty + TTY_Config.old_tty
        mov     rax, SYS_IOCTL
        mov     rdi, 0
        mov     rsi, TCGETS
        syscall
        
        ;; Get another copy of initial tty state (to modify) :
        mov     rdx, tty + TTY_Config.tty
        mov     rax, SYS_IOCTL
        mov     rdi, 0
        mov     rsi, TCGETS
        syscall
        
        ;; Switch off linux console 'cooked mode' idiocy:
        and     dword [tty + TTY_Config.lflag], ~(0xF)
        
        ;; Set the modified tty state:
        mov     rdx, tty + TTY_Config.tty
        mov     rax, SYS_IOCTL
        mov     rdi, 0
        mov     rsi, TCPUTS
        syscall
        ret
;-----------------------------------------------------------------------------
_Uncure_TTY: ;; Set original tty state again:
        mov     rdx, tty + TTY_Config.old_tty
        mov     rax, SYS_IOCTL
        mov     rdi, 0
        mov     rsi, TCPUTS
        syscall
        ret
;-----------------------------------------------------------------------------

;-----------------------------------------------------------------------------
; I/O
;-----------------------------------------------------------------------------
_Write_Char:
        PUSHA
        mov     byte [IOBUF], dl
        mov     rdx, 1
        mov     rax, SYS_WRITE
        mov     rsi, IOBUF
        mov     rdi, STDOUT
        syscall
        POPA
        ret

;; return char in IOBUF
_Read_Char_Blocking:
        PUSHA
        mov     rdi, 0      ; STDIN
        mov     rsi, IOBUF  ; where to put
        mov     rdx, 1      ; read one char
        mov     rax, 0
        syscall
        POPA
        ret
;-----------------------------------------------------------------------------

;-----------------------------------------------------------------------------
; Transmit string to STDERR. RDX points to length (32bit) after which is text.
;-----------------------------------------------------------------------------
_Print_Text_STDERR:
        PUSHA
        mov     rdi, STDERR      ; Destination
        lea     rsi, [rdx + 4]   ; Start of text
        mov     rax, SYS_WRITE   ; SYS_WRITE
        mov     edx, dword [edx] ; Length of text
        syscall                  ; Transmit the text to STDERR
        POPA
        ret
;-----------------------------------------------------------------------------

;-----------------------------------------------------------------------------
; Print hex value of EAX to STDOUT.
;-----------------------------------------------------------------------------
; _Dump_Byte:
;         PUSHA
;         mov     ebp, eax
;         shr     eax, 4
;         call    _dig
;         mov     eax, ebp
;         call    _dig
;         POPA
;         ret

; _Dump_EAX:
;         PUSHA
;         mov     ebp, eax
;         mov     ebx, 28
; _do_dig:
;         mov     eax, ebp
;         mov     ecx, ebx
;         shr     eax, cl
;         call    _dig
;         sub     ebx, 4
;         jnc     _do_dig
;         POPA
;         ret
; _dig:
;         and     eax, 0xF
;         mov     rsi, _digits
;         add     rsi, rax
;         mov     rdx, 0x1
;         mov     rax, SYS_WRITE
;         mov     rdi, STDOUT
;         syscall
;         ret
;-----------------------------------------------------------------------------

section .rodata

; _linefeed:  db 0xA, 0
_digits:    db "0123456789abcdef", 0