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[/] [open8_urisc/] [trunk/] [VHDL/] [o8_cpu.vhd] - Rev 183

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Rev Log message Author Age Path
183 Renamed core to o8_cpu to match new naming scheme jshamlet 1751d 02h /open8_urisc/trunk/VHDL/o8_cpu.vhd
182 Simplified the address generation logic at the expense of making LDX take one additional clock cycle. This allowed the address logic to be split out of the main state machine and simplified (greatly). During this process, a bug in SDO was found and fixed that caused it to return through the wrong pipe fill state wnen auto increment was disabled. jshamlet 1751d 02h /open8_urisc/trunk/VHDL/Open8.vhd
181 Altered the RSP instruction to allow the stack pointed to either be restored from registers or stored to registers based on the status of a processor bit. Also modified LDX to simplify the address logic. jshamlet 1751d 22h /open8_urisc/trunk/VHDL/Open8.vhd
172 General code cleanup jshamlet 3276d 00h /open8_urisc/trunk/VHDL/Open8.vhd
169 Corrected issue with CMP and SBC generating an inverted carry flag and added new constants to the package file to simplify interfacing new modules. jshamlet 3331d 01h /open8_urisc/trunk/VHDL/Open8.vhd
168 Simplified write data path logic,
Converted RTC to packed BCD,
Corrected several bugs in real time clock component,
jshamlet 4109d 21h /open8_urisc/trunk/VHDL/Open8.vhd
167 Updated CPU model; Pipelined ALU control signals to improve fMAX, corrected issue with interrupt controller priority not being obeyed, fixed bug in auto-indexing instructions where the upper register wasn't being properly incremented, cleaned up code to make the processor model easier to follow.
Added several useful modules that use the Open8 bus.
jshamlet 4117d 19h /open8_urisc/trunk/VHDL/Open8.vhd
164 Modified the data path to allow the bus to go idle while waiting for an interrupt. This makes it easier to debug code that uses the WAI instruction, as both Wr_Enable and Rd_Enable go low. jshamlet 4753d 15h /open8_urisc/trunk/VHDL/Open8.vhd
162 Added optional generic to specify that the BRK instruction implements a WAit_for_Interrupt (WAI) instruction instead. Logically emulates INT, but without triggering a soft interrupt. Note that the NOP instruction maps to BRK, and will not function correctly if this option is set. jshamlet 4844d 08h /open8_urisc/trunk/VHDL/Open8.vhd
156 Optimized for timing,
Flattened block structure to single entity.
jshamlet 4900d 22h /open8_urisc/trunk/VHDL/Open8.vhd
155 Fixed additional interrupt logic bug,
Optimized several blocks - including ALU, stack, program counter, and data path.
jshamlet 4901d 17h /open8_urisc/trunk/VHDL/Open8.vhd
154 Fixed problem with missing data path override in interrupt logic. Should resolve issues with processor crashing when an interrupt occurs as a STO instruction is being executed. jshamlet 4906d 20h /open8_urisc/trunk/VHDL/Open8.vhd
153 Fixed bug in interrupt logic that caused stack pointer to increment if interrupt occurred as specific instructions were being decoded,
Fixed bug in interrupt logic where instruction caching would remain enabled during an interrupt, causing improper execution depending on what instruction was in the decode stage as the interrupt is trigered.
jshamlet 4933d 16h /open8_urisc/trunk/VHDL/Open8.vhd
151 Fixed STO instruction and interrupt logic to avoid address bus corruption issues. jshamlet 4943d 19h /open8_urisc/trunk/VHDL/Open8.vhd
10 corrected implementation for BTT to match V8/ARClite definition, changed sense of reset, corrected comments to match source values khays 5085d 04h /open8_urisc/trunk/VHDL/Open8.vhd
8 Need to learn SVN... jshamlet 5413d 15h /open8_urisc/trunk/VHDL/Open8.vhd
7 Initial Upload jshamlet 5413d 15h /open8_urisc/trunk/open8_urisc/VHDL/Open8.vhd

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