Add version switch

src/args.S

@@ -94,7 +94,7 @@ fetch_argv:
 
 # Check if flag was given
 # @param[in] a0: ptr to null-terminated switch 1 (ie. -h).
-# @param[in] a1: ptr to null-terminated switch 2 (ie. --help) (optional).
+# @param[in] a1: ptr to null-terminated switch 2 (ie. --help) (optional, pass 0 for none).
 # @param[out] a0: result code.
 # @param[out] a1: was found (0-not found, 1-found).
 has_switch:
@@ -127,12 +127,14 @@ has_switch:
     mv a1, s0 # move switch ptr 1 addr into a1 (string 1)
     call _str_cmp
     bnez a1, .LSwitchFound # if the strings match, exit loop
+    beqz s1, .LSkipSecondSwitch # if we have no second switch, skip the check
 
     mv a0, s3 # move argv buff addr into a0 (string 0)
     mv a1, s1 # move switch ptr 2 addr into a1 (string 1)
     call _str_cmp
     bnez a1, .LSwitchFound # if the strings match, exit loop
 
+    .LSkipSecondSwitch:
     addi s2, s2, 1 # if string doesn't match we inc to the next arg
     blt s2, s4, .LSwitchProcessNextArg # keep going while we have untested args
     

src/main.S

@@ -11,13 +11,22 @@ help:
     .ascii "Usage: cat [OPTION]... [FILE]...\n"
     .ascii "Concatenate FILE(S) to standard output.\n\n"
     .ascii "With no FILE, or when FILE is -, read standard input.\n\n"
-    .ascii "    -h, --help  |  Show this help page.\n\n"
+    .ascii "    --help       display this help and exit\n"
-    .asciz "Written by lexzach in RISC-V assembly: <https://git.lexza.ch/Lexzach/riscv-cat>\n"
+    .ascii "    --version    output version information and exit\n\n"
+    .asciz "Git repository: <https://git.lexza.ch/Lexzach/riscv-cat>\n"
 .equ HELP_LEN, . - help
 
-flag_h:         .asciz "-h"
+version:
-flag_help:     .asciz "--help"
+    .ascii "cat 1.0.0\n"
+    .ascii "Copyright (C) 2026 lexzach\n"
+    .ascii "License MIT\n"
+    .ascii "This is free software: you are free to change and redistribute it.\n"
+    .ascii "There is NO WARRANTY, to the extent permitted by law.\n\n"
+    .asciz "Written by lexzach in pure RISC-V assembly\n"
+.equ VERSION_LEN, . - version
 
+flag_help:     .asciz "--help"
+flag_version:     .asciz "--version"
 
 .section .text
 .globl _start
@@ -32,18 +41,11 @@ _start:
     call fetch_argc
     mv s0, a1 # store argc
     li s1, 1
-
-    la a0, flag_h
-    la a1, flag_help
-    call has_switch
-    bnez a0, .LMainReturnErr
-    beqz a1, .LSkipDispHelp
-    call _disp_help
-    j .LMainReturnOk
-    .LSkipDispHelp:
     
+    call _check_flags
+
     li t0, 1
-    ble s0, t0, .LProcessStdin # return 1 if no args
+    ble s0, t0, .LProcessStdin # use stdin if no commands
     
     .LProcessFile:
     mv a0, s1
@@ -91,10 +93,39 @@ _start:
     li a7, 93
     ecall   # return 0
 
-_disp_help:
+
-    la a0, 1
+
+_check_flags:
+    addi sp, sp, -8
+    sd ra, 0(sp)
+
+    la a0, flag_help # help flag
+    li a1, 0 # no second flag
+    call has_switch
+    bnez a0, .LMainReturnErr
+    beqz a1, .LSkipDispHelp
+    li a0, 1
     la a1, help
     li a2, HELP_LEN
     li a7, 64
     ecall
+    j .LMainReturnOk
+
+    .LSkipDispHelp:
+    
+    la a0, flag_version # help flag
+    li a1, 0 # no second flag
+    call has_switch
+    bnez a0, .LMainReturnErr
+    beqz a1, .LSkipDispVersion
+    li a0, 1
+    la a1, version
+    li a2, VERSION_LEN
+    li a7, 64
+    ecall
+    j .LMainReturnOk
+    .LSkipDispVersion:
+
+    ld ra, 0(sp)
+    addi sp, sp, 8
     ret