1;   Copyright (C) 2017-2018 Free Software Foundation, Inc.
2;   Contributed by Sebastian Perta.
3;
4; This file is free software; you can redistribute it and/or modify it
5; under the terms of the GNU General Public License as published by the
6; Free Software Foundation; either version 3, or (at your option) any
7; later version.
8;
9; This file is distributed in the hope that it will be useful, but
10; WITHOUT ANY WARRANTY; without even the implied warranty of
11; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12; General Public License for more details.
13;
14; Under Section 7 of GPL version 3, you are granted additional
15; permissions described in the GCC Runtime Library Exception, version
16; 3.1, as published by the Free Software Foundation.
17;
18; You should have received a copy of the GNU General Public License and
19; a copy of the GCC Runtime Library Exception along with this program;
20; see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
21; <http://www.gnu.org/licenses/>.
22
23
24#include "vregs.h"
25
26    .text
27
28START_FUNC ___adddi3
29
30    movw  hl, sp       ; use HL-based addressing (allows for direct addw)
31
32    movw  ax, [hl+4]
33    addw  ax, [hl+12]
34    movw  r8, ax
35
36    mov   a, [hl+6]    ; middle bytes of the result are determined using 8-bit
37    addc  a, [hl+14]   ; ADDC insns which both account for and update the carry bit
38    mov   r10, a       ; (no ADDWC instruction is available)
39    mov   a, [hl+7]
40    addc  a, [hl+15]
41    mov   r11, a
42
43    mov   a, [hl+8]
44    addc  a, [hl+16]
45    mov   r12, a
46    mov   a, [hl+9]
47    addc  a, [hl+17]
48    mov   r13, a
49
50    movw  ax, [hl+10]
51    sknc               ; account for the possible carry from the
52    incw  ax           ; latest 8-bit operation
53    addw  ax, [hl+18]
54    movw  r14, ax
55
56    ret
57
58END_FUNC ___adddi3
59