Mercurial > pub > dyncall > dyncall
comparison doc/disas_examples/arm.atpcs_arm.disas @ 499:fc614cb865c6
- doc and disasexample additions specific to non-trivial C++ aggregates as return values (incl. fixes to doc and additional LSB specific PPC32 section)
| author | Tassilo Philipp |
|---|---|
| date | Mon, 04 Apr 2022 15:50:52 +0200 |
| parents | cb19b2fe2422 |
| children |
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| 498:fd9ba3a6d348 | 499:fc614cb865c6 |
|---|---|
| 828 | 828 |
| 829 ; ... snip, removed code of ctor and copy ctor ... | 829 ; ... snip, removed code of ctor and copy ctor ... |
| 830 | 830 |
| 831 | 831 |
| 832 | 832 |
| 833 ; ---------- C++ trivial and non-trivial aggrs as return values ----------> | |
| 834 ; | |
| 835 ; struct Trivial { int a; }; | |
| 836 ; struct NonTrivial { int a; NonTrivial() : a(0) {} NonTrivial(const NonTrivial& rhs) : a(rhs.a) { } }; | |
| 837 ; | |
| 838 ; extern "C" { | |
| 839 ; struct Trivial f1() { return Trivial(); } | |
| 840 ; } | |
| 841 ; | |
| 842 ; struct NonTrivial f2() { return NonTrivial(); } | |
| 843 ; | |
| 844 ; extern "C" { | |
| 845 ; void f() | |
| 846 ; { | |
| 847 ; int a=1; | |
| 848 ; a += 123; | |
| 849 ; struct Trivial t = f1(); | |
| 850 ; a -= 123; | |
| 851 ; struct NonTrivial n = f2(); | |
| 852 ; a -= 12; | |
| 853 ; } | |
| 854 ; } | |
| 855 | |
| 856 | |
| 857 | |
| 858 ; output from debian-6.0.8-armel w/ gcc 4.4.5 | |
| 859 | |
| 860 00000000 <f1>: | |
| 861 0: e52db004 push {fp} | |
| 862 4: e28db000 add fp, sp, #0 | |
| 863 8: e3a03000 mov r3, #0 | |
| 864 c: e1a00003 mov r0, r3 | |
| 865 10: e28bd000 add sp, fp, #0 | |
| 866 14: e8bd0800 pop {fp} | |
| 867 18: e12fff1e bx lr | |
| 868 | |
| 869 0000001c <_Z2f2v>: | |
| 870 1c: e92d4830 push {r4, r5, fp, lr} | |
| 871 20: e28db00c add fp, sp, #12 | |
| 872 24: e1a04000 mov r4, r0 | |
| 873 28: e1a03004 mov r3, r4 | |
| 874 2c: e1a00003 mov r0, r3 | |
| 875 30: ebfffffe bl 0 ; ctor | |
| 876 34: e1a00004 mov r0, r4 ; ptr to retval space -> r0 | |
| 877 38: e1a00004 mov r0, r4 | |
| 878 3c: e24bd00c sub sp, fp, #12 | |
| 879 40: e8bd4830 pop {r4, r5, fp, lr} | |
| 880 44: e12fff1e bx lr | |
| 881 | |
| 882 00000048 <f>: | |
| 883 48: e92d4800 push {fp, lr} ; | |
| 884 4c: e28db004 add fp, sp, #4 ; | |
| 885 50: e24dd010 sub sp, sp, #16 ; | |
| 886 54: e3a03001 mov r3, #1 ; | |
| 887 58: e50b3008 str r3, [fp, #-8] ; | |
| 888 5c: e51b3008 ldr r3, [fp, #-8] ; | |
| 889 60: e283307b add r3, r3, #123 ; | |
| 890 64: e50b3008 str r3, [fp, #-8] ; | |
| 891 68: ebfffffe bl 0 <f1> ; call f1() | |
| 892 6c: e1a03000 mov r3, r0 ; retval via r0, as small struct | |
| 893 70: e50b300c str r3, [fp, #-12] ; | |
| 894 74: e51b3008 ldr r3, [fp, #-8] ; | |
| 895 78: e243307b sub r3, r3, #123 ; | |
| 896 7c: e50b3008 str r3, [fp, #-8] ; | |
| 897 80: e24b3010 sub r3, fp, #16 ; space to hold non-triv retval -> eax ... | |
| 898 84: e1a00003 mov r0, r3 ; ... as hidden first arg (r0) | |
| 899 88: ebfffffe bl 1c <_Z2f2v> ; call f2() | |
| 900 8c: e51b3008 ldr r3, [fp, #-8] ; | |
| 901 90: e243300c sub r3, r3, #12 ; | |
| 902 94: e50b3008 str r3, [fp, #-8] ; | |
| 903 98: e24bd004 sub sp, fp, #4 ; | |
| 904 9c: e8bd4800 pop {fp, lr} ; | |
| 905 a0: e12fff1e bx lr ; | |
| 906 | |
| 907 | |
| 908 | |
| 833 ; vim: ft=asm68k | 909 ; vim: ft=asm68k |
| 834 | 910 |