diff --git a/lang/src/vec.asm b/lang/src/vec.asm
index 4a21e6c..86c096b 100644
--- a/lang/src/vec.asm
+++ b/lang/src/vec.asm
@@ -23,6 +23,7 @@ global vec_get_or
 global vec_drop
 global vec_find
 global vec_insert
+global vec_insert_many
 global vec_insert_sorted
 global vec_binary_search_by
 
@@ -482,7 +483,7 @@ vec_find:
 ;; rdi: pointer to Vec struct
 ;; rsi : index
 ;; rdx: pointer to data to insert
-;; fn vec_insert(vec: *mut Vec, index: usize, data: *const T, size: usize)
+;; fn vec_insert(vec: *mut Vec, index: usize, data: *const T)
 vec_insert:
     push rbp
     mov rbp, rsp
@@ -530,6 +531,65 @@ vec_insert:
     pop rbp
     ret
 
+;; rdi: pointer to Vec struct
+;; rsi : index
+;; rdx: pointer to data to insert
+;; rcx: count
+;; define-fn: fn vec_insert_many(vec: *mut BlobVec, index: usize, data: *const u8, count: usize)
+vec_insert_many:
+    push rbp
+    mov rbp, rsp
+    push r12
+    push rbx
+    sub rsp, 0x20
+    mov [rsp], rdi              ; save vec
+    mov [rsp + 8], rsi          ; save index
+    mov [rsp + 0x10], rdx       ; save data ptr
+    mov [rsp + 0x18], rcx       ; save count
+
+    mov rsi, [rdi + 8]
+    add rsi, rcx                ; len + count
+    call vec_try_grow
+
+    mov rbx, [rsp]          ; vec
+    mov rdi, [rbx]          ; vec.data
+    mov rcx, [rbx + 24]     ; item_size
+    mov rdx, [rbx + 8]      ; len
+    sub rdx, [rsp + 8]      ; len - index
+    mov rax, rdx
+    mul rcx                 ; (len - index) * item_size
+    mov r12, rax            ; number of bytes to move
+    mov rsi, [rbx]          ; vec.data
+    mov rax, [rsp + 8]      ; index
+    mov rcx, [rbx + 24]     ; item_size
+    mul rcx                 ; index * item_size
+    add rsi, rax            ; src ptr
+    mov rdi, rsi
+
+    mov rax, [rsp + 18]     ; count
+    mul rcx                 ; count * item_size
+    add rdi, rcx            ; dst ptr
+    mov rdx, r12            ; number of bytes to move
+    call memmove
+
+    mov rdi, rsi
+    mov rsi, [rsp + 0x10]
+    mov rdx, [rsp + 0x18]     ; count
+    mov rax, [rbx + 24]     ; item_size
+    mul rdx                 ; count * item_size
+    mov rax, rdx
+    call memcpy
+
+    mov rax, [rbx + 8]      ; len
+    add rax, [rsp + 0x18]    ; len += count
+    mov [rbx + 8], rax
+
+    add rsp, 32
+    pop rbx
+    pop r12
+    pop rbp
+    ret
+
 
 ;; rdi: pointer to Vec struct
 ;; rsi: pointer to key