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apply disconnect logic for command_memory_read/write (#13668)

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Jamiras 2022-02-25 10:23:38 -07:00 committed by GitHub
parent e137f2c9dc
commit e4d62a3b9f
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1 changed files with 26 additions and 4 deletions
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30
command.c
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@ -683,7 +683,7 @@ bool command_version(command_t *cmd, const char* arg)
return true;
}
static const rarch_memory_descriptor_t* command_memory_get_descriptor(const rarch_memory_map_t* mmap, unsigned address)
static const rarch_memory_descriptor_t* command_memory_get_descriptor(const rarch_memory_map_t* mmap, unsigned address, size_t* offset)
{
const rarch_memory_descriptor_t* desc = mmap->descriptors;
const rarch_memory_descriptor_t* end = desc + mmap->num_descriptors;
@ -694,15 +694,37 @@ static const rarch_memory_descriptor_t* command_memory_get_descriptor(const rarc
{
/* if select is 0, attempt to explicitly match the address */
if (address >= desc->core.start && address < desc->core.start + desc->core.len)
{
*offset = address - desc->core.start;
return desc;
}
}
else
{
/* otherwise, attempt to match the address by matching the select bits */
if (((desc->core.start ^ address) & desc->core.select) == 0)
{
/* adjust the address to the start of the descriptor */
unsigned desc_offset = address - (unsigned)desc->core.start;
/* address is unsigned. we only need that much of the disconnect mask */
unsigned mask = (unsigned)desc->core.disconnect;
/* this magic logic is copied from mmap_reduce. it removes any bits from
* address that are non-zero in the disconnect field. bits above the
* removed bits are shifted down to fill the gap. */
while (mask)
{
const unsigned tmp = (mask - 1) & ~mask;
desc_offset = (desc_offset & tmp) | ((desc_offset >> 1) & ~tmp);
mask = (mask & (mask - 1)) >> 1;
}
/* we've calculated the actual offset of the data within the descriptor */
*offset = desc_offset;
/* sanity check - make sure the descriptor is large enough to hold the target address */
if (address - desc->core.start < desc->core.len)
if (desc_offset < desc->core.len)
return desc;
}
}
@ -723,7 +745,8 @@ uint8_t *command_memory_get_pointer(
strlcpy(reply_at, " -1 no memory map defined\n", len);
else
{
const rarch_memory_descriptor_t* desc = command_memory_get_descriptor(&system->mmaps, address);
size_t offset;
const rarch_memory_descriptor_t* desc = command_memory_get_descriptor(&system->mmaps, address, &offset);
if (!desc)
strlcpy(reply_at, " -1 no descriptor for address\n", len);
else if (!desc->core.ptr)
@ -732,7 +755,6 @@ uint8_t *command_memory_get_pointer(
strlcpy(reply_at, " -1 descriptor data is readonly\n", len);
else
{
const size_t offset = address - desc->core.start;
*max_bytes = (desc->core.len - offset);
return (uint8_t*)desc->core.ptr + desc->core.offset + offset;
}