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How does assembly code know if a value is signed or unsigned?

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问题 I get very confused when it seems like sometimes my code treats a certain value as signed and sometimes it treats it as unsigned when comparing values. How does the code know whether a value is signed or unsigned? 回答1: Why do you think that assembly code has to "know" if a value is signed or unsigned? For most operations the results of a signed and an usigned operation are the same: signed int a = 5; signed int b = -6; // 0xFFFFFFFA signed int c; c = a + b; // results in -1 which is

TI-84 random number generation on a computer

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问题 How does the TI-84 randInt function generate random numbers? I would like to replicate this PRNG on my computer so I can get some larger sample sizes, but I'm not sure how. Copying numbers 5 at a time from the calculator isn't an option. Running OS X 10.7.3 回答1: I don't know of how to exactly replicate its function on a computer, however you do not have to generate only five numbers at a time. You can store very large random number samples in lists them transfer them via the ti connect

Bluetooth BLE Android write to peripheral with max throughput

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问题 Our company develops a hardware unit that has Bluetooth BLE and we have a service app in a Nexus 7 (2013) that we want to send firmware files to the unit with. The files can be as large as 500kb. The BT chip is a Texas Instruments CC2540. I have gone through tons of we pages, and scanned Stack overflow for information how to speed up the transfer of data from the Android device to the CC2540, but haven´t found any really good example. On Nordic semiconductors homepage I found an example of

How do I write a memory barrier for a TMS320F2812 DSP?

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I've looked through the TI C/C++ compiler v6.1 user's guide ( spru514e ) but didn't find anything. The asm statement doesn't seem to provide anything in this regard, the manual even warns against changing values of variables (p132). The GNU extension for declaring effects on variables is not implemented (p115). I also didn't find any intrinsic for memory barriers (like __memory_changed() in Keil's armcc). Searching the web or the TI forums also turned up nothing. Any other hints how to proceed? Memory barriers are about the ordering of memory accesses, but you also have to ensure that values

do_install error while running custom bitbake in poky build

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I am using latest poky-am335x to build simple helloworld application. With some workaround I can able to compile the application. I am doing lot of trails to install binaries but build is throwing error. error log : DEBUG: SITE files ['endian-little', 'bit-32', 'arm-common', 'common-linux', 'common-glibc', 'arm-linux', 'arm-linux-gnueabi', 'common'] DEBUG: Executing shell function do_install NOTE: make -j 4 DESTDIR=/home/pis1kor/workspace/poky-am335x/build/tmp/work/armv7a-vfp-neon-poky-linux-gnueabi/helloworld-1.0-r0/image install make: *** No rule to make target `install'. Stop. ERROR: oe

Bluetooth BLE Android write to peripheral with max throughput

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Our company develops a hardware unit that has Bluetooth BLE and we have a service app in a Nexus 7 (2013) that we want to send firmware files to the unit with. The files can be as large as 500kb. The BT chip is a Texas Instruments CC2540. I have gone through tons of we pages, and scanned Stack overflow for information how to speed up the transfer of data from the Android device to the CC2540, but haven´t found any really good example. On Nordic semiconductors homepage I found an example of how they calculate the maximum throughput for a Android unit: ( https://devzone.nordicsemi.com/index.php

How do I convert a floating point C code to fixed point?

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I have a C code which uses doubles. I want to be able to run the code on a DSP ( TMS320 ). But the DSP doesn't support doubles, only fixed-point numbers. What is the best way to convert the code into fixed-point? Is there a good C library for fixed-point numbers (implemented as integers)? TI provides a fixed-point library called "IQmath": http://focus.ti.com/lit/sw/sprc990/sprc990.pdf Converting involves analyzing your current code - for each variable you need to know what range it can hold, and what precision it needs. Then you can decide which type to store it in. IQMath provides types from

How do I convert a floating point C code to fixed point?

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问题 I have a C code which uses doubles. I want to be able to run the code on a DSP (TMS320). But the DSP doesn't support doubles, only fixed-point numbers. What is the best way to convert the code into fixed-point? Is there a good C library for fixed-point numbers (implemented as integers)? 回答1: TI provides a fixed-point library called "IQmath": http://focus.ti.com/lit/sw/sprc990/sprc990.pdf Converting involves analyzing your current code - for each variable you need to know what range it can