View topic - 64-bits access on a 32-bit x86
64-bits access on a 32-bit x86
2 posts
• Page 1 of 1
64-bits access on a 32-bit x86
Hi all
I'm writing the driver for a 64-bit PCI device, and in particular cases
I need to ensure 64-bits accesses to the memory-mapped device region.
Accesses to memory through (volatile unsigned long long*) produce two
"movl" asm instructions, that is not what I want.
Is there a way to be sure the underlying mem access is 64-bits wide,
using x86 assembly? Should I use the MMX "movq" opcode embedded in some
inline asm?
Thanks in advance!
Davide
--
/* Ancri Davide - <davidea at prisma-eng dot it> */
I'm writing the driver for a 64-bit PCI device, and in particular cases
I need to ensure 64-bits accesses to the memory-mapped device region.
Accesses to memory through (volatile unsigned long long*) produce two
"movl" asm instructions, that is not what I want.
Is there a way to be sure the underlying mem access is 64-bits wide,
using x86 assembly? Should I use the MMX "movq" opcode embedded in some
inline asm?
Thanks in advance!
Davide
--
/* Ancri Davide - <davidea at prisma-eng dot it> */
- Davide Ancri
Re: 64-bits access on a 32-bit x86
"Davide Ancri" <falsemail@nospam.xx> wrote in message
news:fe2cdh$gap$1@inn.qnx.com...
x86 doesn't have 64 bit integer operation
*Maybe* that would work depends on a lot of factor. Usually with 64 bit PCI
devices, the 64 bit part becomes usefull for DMA operation.
news:fe2cdh$gap$1@inn.qnx.com...
Hi all
I'm writing the driver for a 64-bit PCI device, and in particular cases
I need to ensure 64-bits accesses to the memory-mapped device region.
Accesses to memory through (volatile unsigned long long*) produce two
"movl" asm instructions, that is not what I want.
x86 doesn't have 64 bit integer operation
Is there a way to be sure the underlying mem access is 64-bits wide,
using x86 assembly? Should I use the MMX "movq" opcode embedded in some
inline asm?
*Maybe* that would work depends on a lot of factor. Usually with 64 bit PCI
devices, the 64 bit part becomes usefull for DMA operation.
Thanks in advance!
Davide
--
/* Ancri Davide - <davidea at prisma-eng dot it> */
- Mario Charest
2 posts
• Page 1 of 1
Who is online
Users browsing this forum: No registered users and 2 guests