[Info-vax] Fortran

[Arne Vajhøj]

On 12/5/2018 7:08 PM, Scott Dorsey wrote:
> =?UTF-8?Q?Arne_Vajh=c3=b8j?=  <arne at vajhoej.dk> wrote:
>> On 12/5/2018 4:01 PM, Scott Dorsey wrote:
>> Why would it be that slow?
>>
>> It seems to fit nicely with a VAX CASEL instruction.
>>
>> But even without it then it would just be calculating an
>> index into the address array and jump to that.
> 
> Computed GO TO is normally calculated and the address looked up from a symbol
> table at runtime.  Just like FORMAT statements are handled at runtime.  I
> guess it seemed like a good idea at the time.
> 
> Because... you could be jumping to any line number anywhere in the whole
> program.

????

A computed goto has a fixed list of statement labels.

GO TO (100,200,300) I

can only go to label 100, 200 and 300.

And I would expect the compiler to store something for the 3
labels that can easily be used to do a jump.

Arne