06 Justenough Information

Just enough information to program a Blackfin 90% of this course can be done knowing less than 10% of the Blackfin Instructions Familiarization assignment for the Analog Devices’ VisualDSP++ Integrated Development Environment

Reminder – Tutorial tomorrow -- Thursday This will help to get ahead on the assignments

Tackled today Recipe for Just in time knowledge  Need a dollop of “C++” code A smizzen of knowledge to build the simplest possible Blackfin assembly language for-loop { } and while { } A pinch of Window’s Experience And a bowl to put the ingredients in (a computer account with password) and somebody else to do all the clean-up (a partner) and a desk in Labs ICT318 and 320.

VisualDSP++ IDE Analog Devices’ integrated development environment (IDE) has been used in the following courses Blackfin – ADSP-BF533 ENCM415 – Assembly language and interfacing (2004) ENCM417 – Switching to Blackfin for 2007 ENCM491 – Real Time Systems (2003) ENEL619.23 -- High speed embedded system architectures (2004) ENEL583/589 – Many 4 th year team projects (2004) TigerSHARC – ADSP-TS201 ENCM515 – Comparative Processor Architectures for DSP (Since 1999) ENEL619.23 -- High speed embedded system architectures (2004)

Just enough to know If time today will do a demo. Build a directory U:/ENCM415/Assignment Remember to insert the BF533 board power plug (check that lights on board flash) Activate VisualDSP -- Log into a station and use Analog devices CONFIGURATOR to set up a “BF533 session” to connect to the hardware Use VisualDSP++ and activate a Blackfin BF533 session – lights should pause Build a Blackfin Project, add to your directory Add your C++ files to the project Compile, Link and Run using the equivalent commands as with Microsoft Visual Basic, Visual Studio etc Add your assembly ASM files to the Blackfin project Compile, Link and Run using the equivalent commands as with Microsoft Visual Basic, Visual Studio etc Don’t forget to add some tests so that you know the code is working

Run VisualDSP – Add New Project

WRITE main.cpp , ADD to Project

Then BUILD (which causes a LOAD) Build and load

Prepare for Assignment – C++ result

Assignment talks about “auto-increment”. Here is how to “try” to get compiler to do it

Prepare main( ) to call assembly code and CHECK the results

We thought we needed the function Assignment1_ASMversion( ) However the linker is worried about not finding _Assignment1_ASMversion__Fv Build WITHOUT ADDING assembly code file Error message is VERY SPECIAL

Standard Format “Assembly code” stub Header info Prologue Code to return value Epilogue

Result using “Assembly code” stub Exactly the result we expected

Keyword – R0 – 32-bit Data Register R0 = 7; // This returns value 7 … Assembly code comment End of line marker 32 bit data register -- R0, R1, R2, R3, R4, R5, R6, R7

Keyword – P0 – 32-bit pointer Register 32 bit pointer register -- P0, P1, P2, P3, P4 Final exam question from last year Careful – when not in the assembler, the linker may give errors which mention p0 which stands for processor 0. The blackfin hardware can come in multi-core version (p0 and p1 for BF561) or multi-processor version.

Keyword 32-bit Frame pointer 32 bit Frame pointer -- FP As on many processors LINK and UNLINK instructions involve hidden operations on FP and SP (stack pointer) More on that in a later class

Keyword – Memory operations 32 bit memory read [ ] – long-word access R0 = [FP + 4]; If FP contains the value 0x20000000 then fetch the 32-bit value starting at memory location 0x20000004 and place in data register R0

Keyword – Memory operations 16 bit memory read W[ ] –word access R1.H = W[FP + 28]; If FP contains the value 0x20000000 then fetch the 16-bit value starting at memory location 0x20000028 and place in data register R1.H which is the UPPER part of the register R1 (R1.H and R1.L)

Keyword – Memory operations 8 bit memory reads are also possible B[FP + 4];

Perhaps time for a working example

Programmer’s model 32 bit data register R0, R1, R2, R3, R4, R5, R6, R7 16 bit data register R0.H, R1.H, R2.H, R3.H ……. R7.H R0.L, R1.L, R2.L, R3.L ………. R7.L 32 bit Pointer register P0, P1, P2, P3, P4 NO 16 bit Pointer registers 32 bit Frame Pointer -- FP 32 bit Stack Pointer -- SP

Memory access MUST be done via a Pointer register 32-bit Memory access Place value 0x2000 into register P1 THEN R0 = [P1] accesses (reads) the 32-bit value at 0x2000 and leaves P1 unchanged (P1 still equals 0x2000) R0 = [P1 + 4] accesses (reads) the 32-bit value at 0x2004 and leaves P1 unchanged (P1 still equals 0x2000) R0 = [P1++] accesses (reads) the 32-bit value at 0x2000 and autoincrements P1 by the size of a long word (4 bytes) (P1 NOW equals 0x2004)

Memory access MUST be done via a Pointer register 16-bit Memory access Place value 0x4000 into register P2 THEN R0 = W[P2] accesses (reads) the 16-bit value at 0x4000 and leaves P2 unchanged (P2 still equals 0x4000) R0 = W[P2 + 4] accesses (reads) the 16-bit value at 0x4004 and leaves P2 unchanged (P2 still equals 0x4000) R0 = W[P2++] accesses (reads) the 16-bit value at 0x4000 and autoincrements P2 by the size of a word (2 bytes) (P2 NOW equals 0x2002)

Just enough to know If time today will do a demo. Build a directory U:/ENCM415/Assignment Remember to insert the BF533 board power plug (check that lights on board flash) Activate VisualDSP Log into a station and use Analog devices CONFIGURATOR to set up a “BF533 session” to connect to the hardware Use VisualDSP++ and activate a Blackfin BF533 session – lights should pause Build a Blackfin Project, add to your directory Add your C++ files to the project Compile, Link and Run using the equivalent commands as with Microsoft Visual Basic, Visual Studio etc Add your ASM files to the project Compile, Link and Run using the equivalent commands as with Microsoft Visual Basic, Visual Studio etc Don’t forget to add some tests so that you know the code is working

06 Justenough Information

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06 Justenough Information