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multiply operation problem
- From: rohitgeek <rohit23taneja at gmail dot com>
- To: gcc-help at gcc dot gnu dot org
- Date: Tue, 24 Nov 2009 07:43:30 -0800 (PST)
- Subject: multiply operation problem
Hi,
I am trying to port a new processor for gcc. Currently, i am able to compile
normal arithmetic and logical instructions by defining respective patterns
in md file. I am stuck at a point where i try to do 16 x 16 multiply
operation to produce 32 bit result and architecture of processor is 32 bit.
1. I am using mulhisi3 pattern but gcc is not picking that up to generate
assembly.
2. Do i need to define particular macros to do operations in HImode ( 16
bit).
3. I am using typecasting in my c program that should logically put 32 bit
result in register, this is my test case
short int a;
short int b;
int c;
a= 10;
b=5;
c = (int) a * b;
I think the problem is in typecasting beacuse in the assembly generated , 0
is moved into the registers and they are multiplied, mean somehow it is not
recongnising what to do in is size modified multiplication.
Please help
Thanks in advance
Rohit
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