| Rev | Line |  | 
|---|
| [9] | 1 | Berkeley Yacc reflects its origins.  The reason so many routines | 
|---|
|  | 2 | use exactly six register variables is that Berkeley Yacc was | 
|---|
|  | 3 | developed on a VAX using PCC.  PCC placed at most six variables | 
|---|
|  | 4 | in registers.  I went to considerable effort to find which six | 
|---|
|  | 5 | variables most belonged in registers.  Changes in machines and | 
|---|
|  | 6 | compilers make that effort worthless, perhaps even harmful. | 
|---|
|  | 7 |  | 
|---|
|  | 8 | The code contains many instances where address calculations are | 
|---|
|  | 9 | performed in particular ways to optimize the code for the VAX. | 
|---|
       
      
  Note:
 See   
TracBrowser
 for help on using the repository browser.