X-Git-Url: https://git.danieliu.xyz/?a=blobdiff_plain;f=sped.asm;h=585697bf643d0a2d09f74a024aeda23b8271f264;hb=2505d1841221648a72e768f23a5a475c8e1c01d1;hp=110bf98378f1bd5e012172bb48a69c768c38c04b;hpb=fb894149783dd18e6ecf1271153193a342e80433;p=sped.git

diff --git a/sped.asm b/sped.asm
index 110bf98..585697b 100644
--- a/sped.asm
+++ b/sped.asm
@@ -5,10 +5,33 @@
 
 global main
 extern printf
+extern fflush
+extern stdout
+
+; macros
+%macro write_str 2
+    mov eax, 4
+    mov ebx, 1
+    mov ecx, %1
+    mov edx, %2
+    int 0x80
+%endmacro
 
 section .data
     banner_str db `SPED - the stupidly pointless editor\n`, 0x00
     nofile_str db `no file provided\n`, 0x00
+    readlines_str db `opened file with %i lines\n`, 0x00
+    prompt_str db `sped > `, 0x00
+    invalidcmd_str db `invalid command\n`, 0x00
+    invalidaddr_str db `invalid address\n`, 0x00
+    charcount_str db `read %i chars\n`, 0x00
+    currentline_str db `current line: %i\n`, 0x00
+    echo_str db `%s`, 0x00 ; print strings without format exploit
+
+section .bss
+    buffer resb 4
+    buffer_lines resb 4
+    cur_line resb 4
 
 section .text
 main:
@@ -35,6 +58,16 @@ main:
     push DWORD [ebx]
     call readFile
 
+    mov [buffer], eax
+    mov [buffer_lines], ecx
+    mov DWORD [cur_line], 0x00
+
+    push DWORD [buffer_lines]
+    push readlines_str
+    call printf
+
+    call repl
+
     mov eax, 0
     jmp _main_exit
 
@@ -46,3 +79,127 @@ main:
     pop ebp
     ret
 
+; prompt for user
+; no args - reads from globals
+repl:
+
+    %define CMDSTR 4 ; the previous line read from user
+
+    push ebp
+    mov ebp, esp
+
+    sub esp, 4
+
+    _repl_loop:
+    
+    ; print the prompt
+    push prompt_str
+    call printf
+    push DWORD [stdout]
+    call fflush
+
+    ; read line from stdin
+    push 0
+    call readLine
+
+    mov DWORD [ebp-CMDSTR], eax
+
+    ; commands are single char for now
+    cmp ecx, 1 
+    jne _repl_invalid_cmd
+
+    ; parse commands
+    mov eax, DWORD [ebp-CMDSTR]
+    mov eax, [eax]
+
+    ; q exists program
+    mov eax, DWORD [ebp-CMDSTR]
+    cmp BYTE [eax], 'q'
+    jne _repl_cmd_quit_end
+    jmp _repl_exit
+    _repl_cmd_quit_end:
+
+    ; p prints current line
+    mov eax, DWORD [ebp-CMDSTR]
+    cmp BYTE [eax], 'p'
+    jne _repl_cmd_print_end
+
+    mov eax, DWORD [cur_line]
+    mov ecx, 4
+    mul ecx
+    add eax, [buffer]
+    push DWORD [eax]
+    push echo_str
+    call printf
+    jmp _repl_continue
+    _repl_cmd_print_end:
+
+    ; n prints the current line number
+    mov eax, DWORD [ebp-CMDSTR]
+    cmp BYTE [eax], 'n'
+    jne _repl_cmd_number_end
+
+    push DWORD [cur_line]
+    push currentline_str
+    call printf
+
+    jmp _repl_continue
+    _repl_cmd_number_end:
+
+    ; - goes to prev line
+    mov eax, DWORD [ebp-CMDSTR]
+    cmp BYTE [eax], '-'
+    jne _repl_cmd_decline_end
+
+    ; make sure we are within bounds
+    mov eax, DWORD [cur_line] 
+    sub eax, 1
+    cmp eax, 0
+    jl _repl_invalid_addr
+    
+    sub DWORD [cur_line], 1
+
+    jmp _repl_continue
+    _repl_cmd_decline_end:
+
+    ; + goes to next line
+    mov eax, DWORD [ebp-CMDSTR]
+    cmp BYTE [eax], '+'
+    jne _repl_cmd_incline_end
+
+    ; make sure we are within bounds 
+    mov eax, DWORD [cur_line] 
+    add eax, 1
+    cmp eax, [buffer_lines]
+    jge _repl_invalid_addr
+    
+    add DWORD [cur_line], 1
+
+    jmp _repl_continue
+    _repl_cmd_incline_end:
+
+
+    jmp _repl_invalid_cmd
+
+    ; some error messages
+    _repl_invalid_cmd:
+    push invalidcmd_str
+    call printf
+    jmp _repl_continue
+
+    _repl_invalid_addr:
+    push invalidaddr_str
+    call printf
+    jmp _repl_continue
+
+    _repl_continue:
+    jmp _repl_loop
+    
+    _repl_exit:
+
+    %undef CMDSTR
+
+    mov esp, ebp
+    pop ebp
+    ret
+