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rest core function always returns list

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If given a vector, allocates a new Cons for the head
of the list, pointing to the rest of the elements.
This is still O(1), since only needs to copy one element.
This commit is contained in:
Ben Dudson 2017-11-30 23:41:32 +00:00
parent d00896dcad
commit bd1961f76b
1 changed files with 50 additions and 0 deletions
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50
nasm/core.asm
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@ -1398,8 +1398,58 @@ core_rest:
.return_rest:
mov rsi, [rsi + Cons.cdr]
; Check if this is a list or a vector
mov cl, BYTE [rsi]
mov ch, cl
and ch, container_mask
cmp ch, container_list
je .return_list
; Need to allocate a new Cons to replace this first element
call alloc_cons
and cl, content_mask
mov ch, cl ; Save CAR content type in ch
or cl, container_list ; Keep content type, set container type to list
mov [rax], BYTE cl
mov dl, BYTE [rsi + Cons.typecdr] ; CDR type in DL
mov [rax + Cons.typecdr], BYTE dl
; Copy content of CAR and CDR
mov rbx, [rsi + Cons.car]
mov [rax + Cons.car], rbx
mov rcx, [rsi + Cons.cdr]
mov [rax + Cons.cdr], rcx ; Note: Might be pointer
; Check if car contains a pointer
cmp ch, content_pointer
jne .check_cdr
; CAR contains a pointer, so increment reference count
mov r8, rax ; Save return Cons
mov rsi, rbx ; Content of CAR
call incref_object
mov rax, r8 ; Restore return Cons
.check_cdr:
; Check if cdr contains a pointer
cmp dl, content_pointer
jne .return ; Not a pointer, so just return
; A pointer, so increment its reference count
mov rbx, rax ; Save the return Cons
mov rsi, rcx ; The pointer in CDR
call incref_object
mov rax, rbx ; Restore the return Cons
ret
.return_list:
call incref_object
mov rax, rsi
.return:
ret
.return_nil: