High code coverage does not imply higj functional coverage?

stanlly9

這個論壇似乎沒有 Verification 的Topics
2 p$ `2 u4 Z5 c& l: `: B& C我想請教的是：
/ ^% B7 }2 W$ fHigh code coverage雖然是dynamic verification的第一步驟
但是通常並不意味著 一定會有 high functional coverage
3 J1 I; _; J. u& @+ _" ?
請問有人可以舉例嗎?
8 f& v, `9 |( o7 u9 P+ w什麼例子下
會有 high code coverage 但是 functional coverage 卻不高
$ r& K" p# g1 M# @8 f! L[聽說 functional coverage的界定不是很明確...請以自己的想法回答即可

kevin

code coverage:看low level design block(state machine,branch,case...)有幾成已被
run過.不代表function皆work,且符合spec.
Functional Coverage: 看design 的 function spec 有幾成已被check過.
code coverage 與 Functional Coverage是互補的.
做Functional Coverage 也要有 functional coverage model.(跟 ic spec.有關)
6 q" W6 {! c" X6 {* e( ~$ Z; t; e" Q舉個例,一個state machine,輸出順序跟 ic spec相反,code coverage 100%, Functional Coverage 0%.

jarodz

For example,

always @(posedge clk)
7 M* S& R2 E  s  N: ?  C2 Hbegin
- `2 R- x# C9 H- ~$ l      if(A)
( Q# |: M: U9 u" \ Q <= #1 D0;
      else if(B)
1 D  ?, R  K  i5 ]! N, F, a7 ] Q <= #1 D1;
3 m$ A# F8 N1 I8 jend

7 \& H) z8 S- y8 S0 a# \//======================================//
2 l/ e& q* s8 X  ^+ U* _& [
5 z4 u9 q/ Y3 |( \always @(posedge)
' ~7 F: q. h- {" q% x- [ Q <= #1 (A)? D0 : (B)? D1 : Q;
, n* A" F. E& x- T( N; j4 e
The code coverage of second is higher than that of the first.
The code coverage is affected by the coding style.
The more readably code may have a low code coverage.
: @8 q# j8 I- R
Sincrely,
Jarod

masonchung

一般而言
" R) c. Y" ], z- E# V2 PCoverage 有六大類:

Line Coverage
Conditional Coverage
! a) t/ o. Y0 |9 jFSM Coverage
Toggle Coverage
- Y) f7 G8 ]! ~3 C9 x0 g8 TBranch Coverage
Path Coverage

( Q8 ~1 }7 J( M; t1 i3 z有誰能說明這幾種 Coverage 的定義呢?