D - parameter order
- Helmut Leitner <helmut.leitner chello.at> Apr 12 2003
- "Walter" <walter digitalmars.com> Apr 12 2003
- Charles Banas <greywolf greyfade.net> Apr 12 2003
- "Nic Tiger" <nictiger progtech.ru> Apr 13 2003
- "Walter" <walter digitalmars.com> Apr 13 2003
- Charles Banas <greywolf greyfade.net> Apr 13 2003
- Helmut Leitner <helmut.leitner chello.at> Apr 13 2003
- Ilya Minkov <midiclub 8ung.at> Apr 13 2003
- Helmut Leitner <helmut.leitner chello.at> Apr 13 2003
What is the reason that D uses a different ordering (left->right, right->left) of parameters for - functions/methods having fixed parameter lists (e.g. func(i,j)) - functions/methods having variable parameter lists (e. g. func(fmt,...) ? -- Helmut Leitner leitner hls.via.at Graz, Austria www.hls-software.com
Apr 12 2003
"Helmut Leitner" <helmut.leitner chello.at> wrote in message news:3E9848DB.BB70783 chello.at...What is the reason that D uses a different ordering (left->right,
of parameters for - functions/methods having fixed parameter lists (e.g. func(i,j))
It varies depending on the function type (C, Windows, D, etc.). It's best not to rely on a particular order.- functions/methods having variable parameter lists (e. g.
?
For compatibility with C, and the normal way C accesses variable arguments.
Apr 12 2003
On Sat, 12 Apr 2003 13:08:03 -0700, Walter <walter digitalmars.com> wrote:It varies depending on the function type (C, Windows, D, etc.). It's best not to rely on a particular order.
knowledge in most cases. after a quick look through the specs, i don't see if it's documented anywhere, which IMHO, is a problem. if i were to write a snippet of ASM code and needed to call a D function with parameters, how would i do this? -- Charles "grey wolf" Banas
Apr 12 2003
"Nic Tiger" <nictiger progtech.ru> You certainly can declare your D func as extern(C) and interface it from ASM as usual C function (BTW, no mangling weirdness and other). I think it is possible in most cases. Nic Tiger. "Charles Banas" <greywolf greyfade.net> ???????/???????? ? ???????? ?????????: news:oprnj09xca8ctebf news.digitalmars.com...On Sat, 12 Apr 2003 13:08:03 -0700, Walter <walter digitalmars.com> wrote:It varies depending on the function type (C, Windows, D, etc.). It's
not to rely on a particular order.
knowledge in most cases. after a quick look through the specs, i don't
if it's documented anywhere, which IMHO, is a problem. if i were to write a snippet of ASM code and needed to call a D function with parameters, how would i do this? -- Charles "grey wolf" Banas
Apr 13 2003
"Charles Banas" <greywolf greyfade.net> wrote in message news:oprnj09xca8ctebf news.digitalmars.com...On Sat, 12 Apr 2003 13:08:03 -0700, Walter <walter digitalmars.com> wrote:It varies depending on the function type (C, Windows, D, etc.). It's
not to rely on a particular order.
knowledge in most cases. after a quick look through the specs, i don't
if it's documented anywhere, which IMHO, is a problem. if i were to write a snippet of ASM code and needed to call a D function with parameters, how would i do this?
Two choices: 1) declare the function as extern (C) and write your asm function like it was connecting to a C function. 2) use the inline assembler, which will get the right stack offsets for the parameters automatically.
Apr 13 2003
On Sun, 13 Apr 2003 14:13:27 -0700, Walter <walter digitalmars.com> wrote:Two choices: 1) declare the function as extern (C) and write your asm function like it was connecting to a C function.
2) use the inline assembler, which will get the right stack offsets for the parameters automatically.
desirable. though, if the compiler properly inlines, helpful. -- Charles "grey wolf" Banas
Apr 13 2003
Walter wrote:"Helmut Leitner" <helmut.leitner chello.at> wrote in message news:3E9848DB.BB70783 chello.at...What is the reason that D uses a different ordering (left->right,
of parameters for - functions/methods having fixed parameter lists (e.g. func(i,j))
It varies depending on the function type (C, Windows, D, etc.). It's best not to rely on a particular order.
Well, yes, I know.- functions/methods having variable parameter lists (e. g.
?
For compatibility with C, and the normal way C accesses variable arguments.
I understand this. Still I do not understand the need to have two different orderings within D itself. If there is a single cycle of performance you get out of this, ok. But otherwise I would refer to Occam's racor not to deviate from C ordering and not to introduce a piece of complexity unneeded. The way it is makes general fp / dg call interfaces more difficult to construct. -- Helmut Leitner leitner hls.via.at Graz, Austria www.hls-software.com
Apr 13 2003
Helmut Leitner wrote:I understand this. Still I do not understand the need to have two different orderings within D itself. If there is a single cycle of performance you get out of this, ok.
Sure, in current mode (if i understood it correctly), when varargs are used, D uses C calling convention, and when not, a Pascal-like convention, where the called function cleans up the stack, as opposed to C, where the caller does. This results in faster calls and less object code size. The D calling convention is also subject to change to allow for further optimisation. To get a well-defined calling convention, use "extern" C or Pascal option. -i.
Apr 13 2003
Ilya Minkov wrote:Helmut Leitner wrote:I understand this. Still I do not understand the need to have two different orderings within D itself. If there is a single cycle of performance you get out of this, ok.
Sure, in current mode (if i understood it correctly), when varargs are used, D uses C calling convention, and when not, a Pascal-like convention, where the called function cleans up the stack, as opposed to C, where the caller does. This results in faster calls and less object code size.
I hope to understand the advantage of Pascal calling conventions under certain circumstances. But I think the advantage comes from having a fixed size parameter list, not from ordering the parameters (a,b,c) instead of (c,b,a). -- Helmut Leitner leitner hls.via.at Graz, Austria www.hls-software.com
Apr 13 2003