Support packing ints into 0.6 packets

src/multi_protocol.asm

@@ -0,0 +1,33 @@
+; abstraction layer for supporting both 0.6 and 0.7 at the same time
+; basically a bunch of getters that give the right values
+; depending on the current version
+
+get_recv_buf:
+    ; returns into rax either `udp_recv_buf` or `udp_recv6_buf`
+    ; depending on the current connection version
+    mov al, byte [connection_version]
+    cmp al, 7
+    je .version7
+    .version6:
+    mov rax, udp_recv6_buf
+    jmp .end
+    .version7:
+    mov rax, udp_recv_buf
+    .end:
+    ret
+
+get_packet_header_len:
+    ; returns into rax the packet header length
+    ; which is 3 for 0.6 and 7 for 0.7
+    ;
+    push r8
+    mov r8d, PACKET_HEADER_LEN
+    mov al, byte [connection_version]
+    cmp al, 7
+    je .version7
+    mov r8d, PACKET6_HEADER_LEN
+    .version7:
+    ._: ; clear label for debugger
+    mov rax, r8
+    pop r8
+    ret

src/packet.asm

@@ -125,8 +125,15 @@
     mov rax, 0
     mov eax, r9d
 
+    ; r8 is packet header len depending on connection version
+    ; do not overwrite this anywhere in this function!
+    push rax
+    call get_packet_header_len
+    mov r8d, eax
+    pop rax
+
     mov dword edx, [udp_payload_index]
-    lea rdi, [udp_send_buf + PACKET_HEADER_LEN + edx]
+    lea rdi, [udp_send_buf + r8d + edx]
 
     ; _pack_int [rax] [rdi]
     ;  rax = integer
@@ -136,7 +143,7 @@
 
     ; write start
     mov dword edx, [udp_payload_index]
-    lea rdi, [udp_send_buf + PACKET_HEADER_LEN + edx]
+    lea rdi, [udp_send_buf + r8d + edx]
 
     ; rax is the returned write end pointer
     ; calculate amount of bytes written

src/teeworlds_asmr.asm

@@ -143,6 +143,7 @@ section .text
 %include "src/send_game.asm"
 %include "src/receive_control.asm"
 %include "src/receive_control6.asm"
+%include "src/multi_protocol.asm"
 %include "src/system.asm"
 %include "src/string.asm"
 %include "src/packet_header.asm"
@@ -159,20 +160,6 @@ section .text
 %include "src/client_info.asm"
 %include "src/on_chat.asm"
 
-get_recv_buf:
-    ; returns into rax either `udp_recv_buf` or `udp_recv6_buf`
-    ; depending on the current connection version
-    mov al, byte [connection_version]
-    cmp al, 7
-    je .version7
-    .version6:
-    mov rax, udp_recv6_buf
-    jmp .end
-    .version7:
-    mov rax, udp_recv_buf
-    .end:
-    ret
-
 print_udp:
     print_label s_got_udp
     ; hexdump

tests/assert.asm

@@ -76,6 +76,7 @@ section .text
 %include "src/send_game.asm"
 %include "src/receive_control.asm"
 %include "src/receive_control6.asm"
+%include "src/multi_protocol.asm"
 %include "src/system.asm"
 %include "src/string.asm"
 %include "src/packet_header.asm"