Seed the RNG based on current date

dosdl.asm

@@ -5,13 +5,31 @@ org 0x100
 
 section .code
 
-seed equ 20220224
+seed_rng_date:
+	; Get date
+	mov ah, 0x2a
+	int 0x21
+	mov [year], cx
+	mov [month], dh
+	mov [day], dl
 
-; Seed the rng
-mov ax, seed & 0xffff
-mov dx, seed >> 16
-mov bp, rng_seed
-call store32
+	; addl32 = year * 10000
+	mov ax, 10000
+	mul word [year]
+	mov bp, addl32
+	call store32
+
+	; addr32 = month * 100 + day
+	mov ax, 100
+	mul word [month]
+	add ax, [day]
+	mov bp, addr32
+	call store32
+
+	; rng_seed = addl32 + addr32 = year * 10000 + month * 100 + day
+	call add32
+	mov bp, rng_seed
+	call store32
 
 select_target:
 	; Call rng to get a number
@@ -716,6 +734,10 @@ mulr32 dd 0
 addl32 dd 0
 addr32 dd 0
 
+year dw 0
+month dw 0
+day db 0
+
 section .rodata
 
 not_found_str db ' - word not found$'