simplify pollfd deletion: by index

main.s

@@ -41,11 +41,7 @@ pollfds_len     resb 8
 
 SECTION .text
 
-return:
-    ret
-
 %include "server.s"
-%include "pollfds_remove.s"
 
 _start:
     call make_server
@@ -107,7 +103,7 @@ pollfds__scan__found__client:
     mov edi, r14d
     syscall
 
-    mov rdi, r14
+    mov rdi, r15
     call pollfds__remove
 
     pop rdi
@@ -141,6 +137,27 @@ pollfds__append:
     mov [pollfds_len], r10
     ret
 
+; rdi - pollfds array index to remove
+pollfds__remove:
+    mov r11, [pollfds_len]
+    cmp rdi, r10
+    jge return  ; XXX index out of bounds, do some other error?
+    cmp r11, 1
+    jle pollfds__clear
+    mov r10, [pollfds + (r11 - 1) * pollfd_size]
+    mov [pollfds + rdi * pollfd_size], r10
+    sub r11, 1
+    mov [pollfds_len], r11
+    ret
+
+pollfds__clear:
+    mov r10, 0
+    mov [pollfds_len], r10
+    ret
+
+return:
+    ret
+
 exit:
     mov rax, SYS_EXIT
     mov rdi, 0