From 28dfc3448c1eb127834d26b308a0b2e985be79c8 Mon Sep 17 00:00:00 2001
From: Nicholas Tay <nick@windblume.net>
Date: Sun, 22 Oct 2023 22:30:58 +1100
Subject: Implement basic argument handling

---
 pasmgen.asm | 94 ++++++++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 75 insertions(+), 19 deletions(-)

diff --git a/pasmgen.asm b/pasmgen.asm
index bbd4c37..ffcce2c 100644
--- a/pasmgen.asm
+++ b/pasmgen.asm
@@ -1,6 +1,6 @@
 format ELF64 executable
 
-macro genclass class, class_len, caps
+macro genclass class, class_len
 {
  	;; Generate 16 bits (smallest) of randomness from the cpu
  	rdrand ax
@@ -13,45 +13,84 @@ macro genclass class, class_len, caps
 	;; Save output letter into out_buf, bump rcx
 	add rdx, class
 	mov rdx, [rdx]
-	if caps eq 1
-		sub rdx, 32
-	end if
 	mov [rcx], rdx
 	inc rcx
 
 	inc rsi
 }
 
-macro triplet
-{
-	genclass consonants, consonants_len
-	genclass vowels, vowels_len
-	genclass consonants, consonants_len
-}
-
 segment readable executable
 
 entry main
 main:
+	;; No arg preload case
+	cmp [rsp], word 1
+	jne argparse
+
+	mov r8, qword 3
+	mov r9, qword 2
+	mov r10, qword 3
+
+	jmp generate
+	
+argparse:
+	;; Check args (need 3)
+	cmp [rsp], word 3
+	jle fail
+
+	;; load arg1
+	mov r8, [rsp+16]
+	mov r8, [r8]
+	and r8, 0xFF
+	sub r8, 48
+
+	;; load arg2
+	mov r9, [rsp+24]
+	mov r9, [r9]
+	and r9, 0xFF
+	sub r9, 48
+
+	;; load arg3
+	mov r10, [rsp+32]
+	mov r10, [r10]
+	and r10, 0xFF
+	sub r10, 48
+
+generate:
 	;; Store which output byte we're up to in rcx
 	mov rcx, out_buf
 	;; Store chars generated in rsi
 	xor rsi, rsi
 
-	genclass consonants, consonants_len, 1
+tripleter:
+	genclass consonants, consonants_len
 	genclass vowels, vowels_len
 	genclass consonants, consonants_len
-	triplet
-	triplet
-	genclass symbols, symbols_len
+	dec r8
+	test r8, r8
+	jnz tripleter
+symboler:
 	genclass symbols, symbols_len
+	dec r9
+	test r9, r9
+	jnz symboler
+numberer:
 	genclass numbers, numbers_len
-	genclass numbers, numbers_len
-	genclass numbers, numbers_len
+	dec r10
+	test r10, r10
+	jnz numberer
 
+	;; Append new line to string
 	mov [rcx], word 10
 	inc rsi
- 	
+
+	;; Special case to caps the first character
+	xor rax, rax
+	mov al, byte [out_buf]
+	sub al, 32
+	mov rbx, out_buf
+	mov [rbx], al
+
  	;; Write
  	mov rdi, 1  ;; stdout
  	mov rdx, rsi
@@ -63,9 +102,26 @@ main:
  	mov rdi, 0
  	mov rax, 0x3c
  	syscall
+
+fail:
+ 	;; Write
+ 	mov rdi, 1  ;; stdout
+ 	mov rsi, usage
+ 	mov rdx, usage_len
+ 	mov rax, 0x01
+ 	syscall
+ 
+ 	;; Exit 1
+ 	mov rdi, 1
+ 	mov rax, 0x3c
+ 	syscall
+
  
 segment readable writeable
 
+usage db "usage: passmgen [<triplet#> <symbol#> <number#>]", 10
+usage_len = $ - usage
+
 numbers db "0123456789"
 numbers_len = $ - numbers
 vowels db "aeiou"
@@ -75,4 +131,4 @@ consonants_len = $ - consonants
 symbols db "!@#$%&()-=_+[]{}\\|;<>/?."
 symbols_len = $ - symbols
 
-out_buf rb 32
+out_buf rb 64
-- 
cgit