FreeCalypso > hg > tcs211-l1-reconst
view STATUS @ 284:33b35965b4a0
STATUS: began analysis of the differences in the non-exact objects
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Tue, 14 Mar 2017 19:07:14 +0000 |
parents | 974835ad720c |
children | 4d9af8de3973 |
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Objects in l1_ext.lib: l1_afunc.obj: not exact, see explanation below l1_async.obj: perfect match l1_cmplx.obj: perfect match to 20070608 version except line number points l1_init.obj: perfect match l1_pwmgr.obj: perfect match l1_small.obj: perfect match l1_sync.obj: not exact, needs review l1_trace.obj: bits match perfectly, diff only in symbolic metadata l1_dyn_dwl_afunc.obj: perfect match l1_dyn_dwl_apihisr.obj: perfect match l1_dyn_dwl_async.obj: perfect match l1_dyn_dwl_func.obj: not exact, see explanation below l1_dyn_dwl_init.obj: sole diff is in the num_of_primitives oddity, see explanation below l1_dyn_dwl_sync.obj: perfect match l1audio_abb.obj: perfect match l1audio_afunc.obj: bits match perfectly, diff only in symbolic metadata l1audio_async.obj: diffs only in register alloc and symbolic metadata l1audio_back.obj: perfect match l1audio_drive.obj: perfect match l1audio_init.obj: perfect match l1tm_async.obj: bits match perfectly, diff only in the line number points l1tm_func.obj: bits match perfectly, diffs only in symbolic and line numbers l1tm_stats.obj: perfect match Objects in l1_int.lib: dl1_com.obj: not exact, needs review l1_api_hisr.obj: perfect match l1_cmplx_intram.obj: perfect match to 20070608 version l1_ctl.obj: perfect match to 20070608 version l1_drive.obj: perfect match l1_func.obj: perfect match l1_mfmgr.obj: perfect match l1_sync_intram.obj: not exact, needs review l1audio_func.obj: perfect match l1audio_sync.obj: perfect match Objects in l1_custom_ext.lib: l1audio_cust.obj: dead functions not reconstructed, perfect match otherwise l1tm_cust.obj: perfect match l1tm_tpu12.obj: perfect match Objects in l1_custom_int.lib: ind_os.obj: perfect match l1_cust.obj: perfect match Objects in tpudrv.lib: tpudrv.obj: perfect match tpudrv12.obj: not exact, needs review Detailed analysis of differences, i.e., cases where the reconstructed C code compiles into an object that is not bit-identical to the original blob: l1_afunc.obj: The l1_afunc.c module from LoCosto is used without any changes: it compiled right away after adding one constant to l1_const.h, and the result of recompilation is identical to the original up until the l1a_clip_txpwr() function, which is the last function in the module. Disassembly of the original blob version of this function has been analyzed and found to be identical in logic to the available C code, but there must have been some change to the code expression that results in different output from the compiler. In particular, the symbolic info indicates the present of a local variable named power in the original, but no such local var exists in the LoCosto version. The TSM30 version was of no help as it is entirely different there. See g23m/objdiff/l1_ext/l1_afunc.notes for further info. l1_sync.obj: needs further review l1_sync_intram.obj: ditto dl1_com.obj: not exact, needs review l1_dyn_dwl_func.obj: The LoCosto version uses a function (implemented in l1_func.c in the LoCosto code) named l1_memcpy_16bit() to download patch bits into the DSP's API RAM; the function does what the name says, and the logic of using 16-bit accesses when hitting this API RAM makes perfect sense to me (Mychaela). The original TCS211 code apparently used plain memcpy(), which the compiler turned into its C$MEMCPY call. If one does a #define l1_memcpy_16bit memcpy in l1_dyn_dwl_func.c, the resulting l1_dyn_dwl_func.obj is almost bit-identical to the original blob: the only diff is in register allocation - the compiler's register allocator picks a different choice of registers, but all instructions still perfectly line up. For production use of our reconstructed TCS211 L1 code, we have adopted the version with l1_memcpy_16bit() - the function body itself has been moved into l1_dyn_dwl_func.c so that l1_func.c remains a perfect match. l1_dyn_dwl_init.obj: In the TCS211 configuration without L1_GTT, there are a total of 5 signals (aka primitives aka L1 messages) which trigger a dynamic DSP patch download. These 5 signals are enumerated in signal_patch_array[] in l1_dyn_dwl_afunc.c (which has been reconstructed to a perfect match), and their total count (which should be 5) goes into l1a.dyn_dwnld.num_of_primitives, set in l1_dyn_dwnld_initialize_var() in l1_dyn_dwl_init.c. In the original blob version this num_of_primitives variable ends up being set to 6: first set to 2, then incremented by 4. In the LoCosto source this var is first set to 0 as they apparently have no patches that are independent of compilation config options, and then incremented for every enabled option. In our reconstruction we have made the GPRS and AMR_SCH patches and the primitives that trigger them mandatory, and conditionalized the E2 and AMR_MMS patches on MELODY_E2. The GPRS and AMR_MMS critters are preinstalled by the static patch, and get pushed out by AMR_SCH and E2, respectively. Of the 5 primitives listed in signal_patch_array[] in the original blob, the first 2 are always-present core ones, whereas the last 3 are specific to E2. The AMR_MMS patch is reinstated upon L1_BACK_MELODY_E2_UNLOAD_INSTRUMENT_CON. Based on the above reasoning, our reconstructed version sets l1a.dyn_dwnld.num_of_primitives to 5 in the full configuration: first sets to 2, then increments by 3. If one makes a sans-MELODY_E2 build, only the GPRS and AMR_SCH patches will be retained, and only the two non-E2 primitives for entry into and exit from dedicated mode. l1audio_async.obj: The only bit diff is in register allocation - the compiler's register allocator picks a different choice of registers, but all instructions still perfectly line up. There is also a slight diff in the symbolic metadata emitted for functions, which might be related to the diff in the register allocation. The root cause of these diffs could not be found, but there is no functional difference as only some in-function temporary registers have been interchanged. l1audio_cust.obj: The original blob version has these demo/test functions at the end of the module: audio_melo_e1_demo1_start() audio_melo_e1_demo1_stop() audio_melo_e1_demo2_start() audio_melo_e1_demo2_stop() audio_melo_e2_load_lsi() audio_melo_e2_demo1_start() audio_melo_e2_demo1_stop() audio_melo_e2_demo2_start() audio_melo_e2_demo2_stop() These functions are dead code, i.e., they are not called or referenced from anywhere else in the firmware, and the link succeeds without them being present. These dead functions have been omitted from the reconstructed version. The reconstruction is a perfect match otherwise. tpudrv12.obj: early reconstruction, needs further review