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diff --git a/target-sh4/README.sh4 b/target-sh4/README.sh4 deleted file mode 100644 index b887175..0000000 --- a/target-sh4/README.sh4 +++ /dev/null @@ -1,150 +0,0 @@ -qemu target: sh4 -author: Samuel Tardieu <sam@rfc1149.net> -last modified: Tue Dec 6 07:22:44 CET 2005 - -The sh4 target is not ready at all yet for integration in qemu. This -file describes the current state of implementation. - -Most places requiring attention and/or modification can be detected by -looking for "XXXXX" or "assert (0)". - -The sh4 core is located in target-sh4/*, while the 7750 peripheral -features (IO ports for example) are located in hw/sh7750.[ch]. The -main board description is in hw/shix.c, and the NAND flash in -hw/tc58128.[ch]. - -All the shortcomings indicated here will eventually be resolved. This -is a work in progress. Features are added in a semi-random order: if a -point is blocking to progress on booting the Linux kernel for the shix -board, it is addressed first; if feedback is necessary and no progress -can be made on blocking points until it is received, a random feature -is worked on. - -Goals ------ - -The primary model being worked on is the soft MMU target to be able to -emulate the Shix 2.0 board by Alexis Polti, described at -http://perso.enst.fr/~polti/realisations/shix20/ - -Ultimately, qemu will be coupled with a system C or a verilog -simulator to simulate the whole board functionalities. - -A sh4 user-mode has also somewhat started but will be worked on -afterwards. The goal is to automate tests for GNAT (GNU Ada) compiler -that I ported recently to the sh4-linux target. - -Registers ---------- - -16 general purpose registers are available at any time. The first 8 -registers are banked and the non-directly visible ones can be accessed -by privileged instructions. In qemu, we define 24 general purpose -registers and the code generation use either [0-7]+[8-15] or -[16-23]+[8-15] depending on the MD and RB flags in the sr -configuration register. - -Instructions ------------- - -Most sh4 instructions have been implemented. The missing ones at this -time are: - - FPU related instructions - - LDTLB to load a new MMU entry - - SLEEP to put the processor in sleep mode - -Most instructions could be optimized a lot. This will be worked on -after the current model is fully functional unless debugging -convenience requires that it is done early. - -Many instructions did not have a chance to be tested yet. The plan is -to implement unit and regression testing of those in the future. - -MMU ---- - -The MMU is implemented in the sh4 core. MMU management has not been -tested at all yet. In the sh7750, it can be manipulated through memory -mapped registers and this part has not yet been implemented. - -Exceptions ----------- - -Exceptions are implemented as described in the sh4 reference manual -but have not been tested yet. They do not use qemu EXCP_ features -yet. - -IRQ ---- - -IRQ are not implemented yet. - -Peripheral features -------------------- - - + Serial ports - -Configuration and use of the first serial port (SCI) without -interrupts is supported. Input has not yet been tested. - -Configuration of the second serial port (SCIF) is supported. FIFO -handling infrastructure has been started but is not completed yet. - - + GPIO ports - -GPIO ports have been implemented. A registration function allows -external modules to register interest in some port changes (see -hw/tc58128.[ch] for an example) and will be called back. Interrupt -generation is not yet supported but some infrastructure is in place -for this purpose. Note that in the current model a peripheral module -cannot directly simulate a H->L->H input port transition and have an -interrupt generated on the low level. - - + TC58128 NAND flash - -TC58128 NAND flash is partially implemented through GPIO ports. It -supports reading from flash. - -GDB ---- - -GDB remote target support has been implemented and lightly tested. - -Files ------ - -File names are harcoded at this time. The bootloader must be stored in -shix_bios.bin in the current directory. The initial Linux image must -be stored in shix_linux_nand.bin in the current directory in NAND -format. Test files can be obtained from -http://perso.enst.fr/~polti/robot/ as well as the various datasheets I -use. - -qemu disk parameter on the command line is unused. You can supply any -existing image and it will be ignored. As the goal is to simulate an -embedded target, it is not clear how this parameter will be handled in -the future. - -To build an ELF kernel image from the NAND image, 16 bytes have to be -stripped off the end of every 528 bytes, keeping only 512 of them. The -following Python code snippet does it: - -#! /usr/bin/python - -def denand (infd, outfd): - while True: - d = infd.read (528) - if not d: return - outfd.write (d[:512]) - -if __name__ == '__main__': - import sys - denand (open (sys.argv[1], 'rb'), - open (sys.argv[2], 'wb')) - -Style isssues -------------- - -There is currently a mix between my style (space before opening -parenthesis) and qemu style. This will be resolved before final -integration is proposed. |