# Questions tagged [hazard]

13 questions

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### About data hazard and forwarding with beq in MIPS?

Why the first add needs forwarding?
# stage:
add $1, $2, $3 # WB
add $4, $5, $6 # MEM
nop # EX
beq $1, $4, target # ID
Since beq needs the $1, if the first add is about to execute WB-stage, isn't that no forwarding needed since beq at ID-stage, which is about to read the r...

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### MIPS pipeline load use hazard with branch

Today I'm studying in the MIPS pipeline and finding out one interesting thing.
Seeing the code below:
I1: lw $s1, 0($s3)
I2: add $s4, $s5, $zero
I3: beq $s1, $s5, 8
In order to reduce penalty of branch, we make compare two register data in ID stage.
Making me confuse is that whether this condition...

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### PIPELINE - mem(memory) and if(instruction fetch)

In PIPELINE, MEM (memory) and IF (instruction fetch) are the same hardware element?
If are the same memory then 2 instructions can't load or store in the same cycle clock, I'm right?
MIPS processor diagram

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### Does expected value of F(x)/x(1-F(x)) have a name, F(x) is CDF? Is it related to hazard function?

I was solving a problem and encountered the following:
\sum (f(x)/x) (F(x)/(1-F(x))
Here f(x) is pmf and F(x) is CDF. Is expected value of F(x)/x(1-F(x)) a known function? I found out that f(x)/(1-F(x)) is called hazard function. Also, x is defined over positive values. It can be assumed that x is b...

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### model to evaluate disease worsening/improvement after a therapy change

I have some experience with regression analysis, cox models etc., but I would like to ask which model would suite best to evaluate a chronic disease symptomatic control associated with different drug changes.
Suppose you have a time-series data for several patients, with a categorical variable that...

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### How to compare hazard ratios of different levels in Cox regression from R output?

I've run a Cox regression model with a categorical predictor and I'm not sure whether I can compare the different levels to each other, or just to the reference category?
For example, in the lung dataset:
lung$ph.ecog=factor(lung$ph.ecog)
fit1=coxph(Surv(lung$time, lung$status) ~ ph.ecog, data=lung...

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### Plot True and Estimated Hazard Rate Functions

I want to plot true and estimated Hazard rate functions by using following code. But its quit disturbed. I want such a plot which has like 2 lines to show the both.
Code
require(VGAM)
n

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132

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### Does anything short of __syncthreads() prevent read-after-write intra-warp shared memory hazards?

I have a warp which writes some data to shared memory - with no overwrites, and soon after reads from shared memory. While there may be other warps in my block, they're not going to touch any part of that shared memory or write to anywhere my warp of interest reads from.
Now, I recall that despite w...

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123

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### Basic Calculations with stat_functions — Plotting hazard functions

I am currently trying to plot some density distributions functions with R's ggplot2. I have the following code:
f

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116

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### Static Hazard 1 and One Circuit Problems?

I read about Static Hazard. We know Static 1-hazard is: Input change causes output to go from 1 to 0 to 1.
My note covers a Circuit as follows:
My notes says: When B=C=D=1, for any changes in A values, it's probable to have Static Hazard 1.
But I think:
for 1 to 0 transition of A static hazard 1...

2

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674

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### MIPS language to avoid pipeline stalls

Regarding the MIPS assembly language which is thought in the pattersson's book, I have a question with inserting NOP between instructions to avoid pipeline stalls.
Consider the following code
lw $s5, -16($s5)
sw $s5, -16($s5)
add $s5, $s5, $s5
We see there is a RAW hazard for $s5 between lw and...

3

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59

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### a specific case of data hazard( when a R-Type instruction comes after two consecutive LW )

I am designing a MIPS-like CPU with Verilog and now I'm handling data hazards.
I have these instructions:
Ins[0] = LW r1 r0(100)
Ins[1] = LW r2 r0(101)
Ins[2] = ADD r3 r2 r1
I'm using pipeline and my dataPath is something like this:
I have 5 stages, with 4 latch buffers separating them.
The problem...

5

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436

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### calculating hazard function in R for the standard normal distribution

Based on formulas given in the Mathematica UUPDE database
http://blog.wolfram.com/2013/02/01/the-ultimate-univariate-probability-distribution-explorer/
I've plotted the hazard function standard normal distribution in R.
It seems to be correct in certain range, the numerical issues occur for larger...