Mercurial > pub > dyncall > dyncall

changeset 614:b74d7a249642

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
disas example for explicit cdecl declared thiscall
author Tassilo Philipp
date Sat, 01 Oct 2022 16:04:40 +0200
parents 3c3e321875f7
children 516d72e98253
files doc/disas_examples/x86.cdecl.disas doc/disas_examples/x86.fastcall_borland.disas
diffstat 2 files changed, 60 insertions(+), 3 deletions(-) [+]
line wrap: on
line diff
--- a/doc/disas_examples/x86.cdecl.disas	Sat Oct 01 16:03:25 2022 +0200
+++ b/doc/disas_examples/x86.cdecl.disas	Sat Oct 01 16:04:40 2022 +0200
@@ -790,5 +790,59 @@
 
 
 
+; ---------- cdecl-declared (explicit) C++ thiscall w/ msvc ---------->
+;
+; class C {
+; public:
+;     float __cdecl m(int i) const { return float(i + 123); }
+; };
+;
+; extern "C" {
+;     float f()
+;     {
+;         C c;
+;         return c.m(27);
+;     }
+; }
+
+
+
+; output from godbolt compiler explorer w/ msvc 19.0
+
+tv68 = -8
+tv67 = -4
+_i$ = 12
+float C::m(int)const  PROC
+        push    ebp                      ;
+        mov     ebp, esp                 ;
+        sub     esp, 8                   ;
+        mov     eax, DWORD PTR _i$[ebp]  ;
+        add     eax, 123                 ; |
+        mov     DWORD PTR tv67[ebp], eax ; / in arg + 123, pushed onto stack
+        fild    DWORD PTR tv67[ebp]      ; \
+        fstp    DWORD PTR tv68[ebp]      ; | float cast and put return value in fp0
+        fld     DWORD PTR tv68[ebp]      ; |
+        mov     esp, ebp                 ;
+        pop     ebp                      ;
+        ret     0                        ;
+float C::m(int)const  ENDP
+
+_c$ = -1
+_f      PROC                             ;
+        push    ebp                      ;
+        mov     ebp, esp                 ;
+        push    ecx                      ;
+        push    27                       ; arg 1
+        lea     eax, DWORD PTR _c$[ebp]  ; |
+        push    eax                      ; | arg 0 (this ptr)
+        call    float C::m(int)const     ; call C::m()
+        add     esp, 8                   ;
+        mov     esp, ebp                 ;
+        pop     ebp                      ;
+        ret     0                        ;
+_f      ENDP
+
+
+
 ; vim: ft=asm
 
--- a/doc/disas_examples/x86.fastcall_borland.disas	Sat Oct 01 16:03:25 2022 +0200
+++ b/doc/disas_examples/x86.fastcall_borland.disas	Sat Oct 01 16:04:40 2022 +0200
@@ -5,7 +5,7 @@
 ;     __int32 i2;
 ; };
 ; #pragma pack(pop)
-; 
+;
 ; TTest __fastcall DoTest()
 ; {
 ;     TTest t;
@@ -13,13 +13,14 @@
 ;     t.i2 = 2;
 ;     return t;
 ; }
-; 
+;
 ; ...
 ; TTest t = DoTest();
 
+
+
 ; from http://codeverge.com/embarcadero.cppbuilder.cpp/does-fastcall-have-any-bearing-on/1043767
 
-
 DoTest():
   push ebp                     ; |
   mov ebp,esp                  ; | prolog
@@ -37,5 +38,7 @@
   pop ebp                      ; | epilog
   ret                          ; |
 
+
+
 ; vim: ft=asm