aboutsummaryrefslogtreecommitdiff
path: root/backends/platform/ds
diff options
context:
space:
mode:
authorTony Puccinelli2010-07-20 04:04:13 +0000
committerTony Puccinelli2010-07-20 04:04:13 +0000
commit3d3e4e6c397a58d21dbc3be7fbe0c0173f193644 (patch)
treefe4a972f5c40a5a3c9d62bc28959cb54b6f314bf /backends/platform/ds
parentd5f442dc6bd63cfcdef2eae88b7e10f9671436ba (diff)
downloadscummvm-rg350-3d3e4e6c397a58d21dbc3be7fbe0c0173f193644.tar.gz
scummvm-rg350-3d3e4e6c397a58d21dbc3be7fbe0c0173f193644.tar.bz2
scummvm-rg350-3d3e4e6c397a58d21dbc3be7fbe0c0173f193644.zip
coded for more relocations, added check for RELA type relocations, added comments
svn-id: r51048
Diffstat (limited to 'backends/platform/ds')
-rw-r--r--backends/platform/ds/arm9/source/dsloader.cpp55
1 files changed, 52 insertions, 3 deletions
diff --git a/backends/platform/ds/arm9/source/dsloader.cpp b/backends/platform/ds/arm9/source/dsloader.cpp
index 2f953cc33b..c0e8b63dbc 100644
--- a/backends/platform/ds/arm9/source/dsloader.cpp
+++ b/backends/platform/ds/arm9/source/dsloader.cpp
@@ -97,16 +97,18 @@ bool DLObject::relocate(Common::SeekableReadStream* DLFile, unsigned long offset
int a = 0;
unsigned int relocation = 0;
+ // Loop over relocation entries
for (int i = 0; i < cnt; i++) {
+ // Get the symbol this relocation entry is referring to
Elf32_Sym *sym = (Elf32_Sym *)(_symtab) + (REL_INDEX(rel[i].r_info));
+ // Get the target instruction in the code
unsigned int *target = (unsigned int *)((char *)relSegment + rel[i].r_offset);
unsigned int origTarget = *target; // Save for debugging
- //DBG("%d, ", REL_TYPE(rel[i].r_info));
-
+ // Act differently based on the type of relocation
switch (REL_TYPE(rel[i].r_info)) {
case R_ARM_ABS32:
@@ -151,6 +153,48 @@ bool DLObject::relocate(Common::SeekableReadStream* DLFile, unsigned long offset
}
break;
+ case R_ARM_CALL:
+ if (sym->st_shndx < SHN_LOPROC) { // Only shift for plugin section.
+ a = *target & 0x00ffffff;
+ a = (a << 8) >> 6; // Calculate addend by sign-extending (insn[23:0] << 2)
+ relocation = a + (Elf32_Addr)_segment; // Shift by main offset
+
+ /*TODO:
+ * if (SYM_TYPE(sym->st_info) == STT_FUNC && symbol addresses a thumb instruction) {
+ * relocation |= 1;
+ * }
+ */
+
+ relocation = relocation - rel[i].r_offset;
+ relocation = relocation >> 2;
+ *target &= 0xff000000; // Clean lower 26 target bits
+ *target |= (relocation & 0x00ffffff);
+
+ DBG("R_ARM_CALL: i=%d, a=%x, origTarget=%x, target=%x\n", i, a, origTarget, *target);
+ }
+ break;
+
+ case R_ARM_JUMP24:
+ if (sym->st_shndx < SHN_LOPROC) { // Only shift for plugin section.
+ a = *target & 0x00ffffff;
+ a = (a << 8) >> 6; // Calculate addend by sign-extending (insn[23:0] << 2)
+ relocation = a + (Elf32_Addr)_segment; // Shift by main offset
+
+ /*TODO:
+ * if (SYM_TYPE(sym->st_info) == STT_FUNC && symbol addresses a thumb instruction) {
+ * relocation |= 1;
+ * }
+ */
+
+ relocation = relocation - rel[i].r_offset;
+ relocation = relocation >> 2;
+ *target &= 0xff000000; // Clean lower 26 target bits
+ *target |= (relocation & 0x00ffffff);
+
+ DBG("R_ARM_CALL: i=%d, a=%x, origTarget=%x, target=%x\n", i, a, origTarget, *target);
+ }
+ break;
+
case R_ARM_V4BX:
DBG("R_ARM_V4BX: No relocation calculation necessary\n");
break;
@@ -365,12 +409,17 @@ bool DLObject::relocateRels(Common::SeekableReadStream* DLFile, Elf32_Ehdr *ehdr
Elf32_Shdr *curShdr = &(shdr[i]);
//Elf32_Shdr *linkShdr = &(shdr[curShdr->sh_info]);
- if (curShdr->sh_type == SHT_REL && // Check for a relocation section
+ if ((curShdr->sh_type == SHT_REL || curShdr->sh_type == SHT_RELA) && // Check for a relocation section
curShdr->sh_entsize == sizeof(Elf32_Rel) && // Check for proper relocation size
(int)curShdr->sh_link == _symtab_sect && // Check that the sh_link connects to our symbol table
curShdr->sh_info < ehdr->e_shnum && // Check that the relocated section exists
(shdr[curShdr->sh_info].sh_flags & SHF_ALLOC)) { // Check if relocated section resides in memory
+ if (curShdr->sh_type == SHT_RELA) {
+ seterror("RELA entries not supported for ARM yet!\n");
+ return false;
+ }
+
if (!relocate(DLFile, curShdr->sh_offset, curShdr->sh_size, _segment)) {
return false;
}