Like many old sayings, it's worth what you paid for it. The z instruction set includes operations far more powerful than anything in C, and the lack of a Turing complete macro language makes C highly inflexible.
C may be similar to SOAP 2 on the 650; it's certainly not similar to any assembler that I used in the last half century. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Assembler List <[email protected]> on behalf of Martin Ward <[email protected]> Sent: Tuesday, January 23, 2018 4:26 PM To: [email protected] Subject: Re: Fair comparison C vs HLASM There is an old saying "C combines the power of assembly language with the flexibility of assembly language": the point being that C as a language is very close to assembly language. C has few of the powerful abstraction features found in modern programming languages: automated memory allocation and garbage collection, first class functions, higher order functions, closures, hash tables, abstract data types and so on. C and HLASM both have support for basic, low-level programming features such as prodecure calls, conditional statements and while/repeat loops. Both require the programmer to express their code at a very low level: "close to the metal". The main advantage of C over HLASM is that C has an optimising compiler. If performance is of ultimate importance (and why would anyone use such low-level languages otherwise?) then the C compiler can automatically provide register allocation, loop unrolling and procedure inlining where heuristics indicate these transformations will improve performance. A good assembler programmer might make reasonable choices for register allocation on first writing the program: but will they be willing to recalculate a new register allocation after each addition or modification to the program? Will they choose to write optimal, but unstructured and unmaintainable spaghetti code or readable but less efficient structured code? With a compiler, the programmer can write structured code and allow the optimiser to apply common subexpression elimination, pointer chasing, loop unrolling, procedure inlining, and so on, creating mode efficient code which would be unmaintainable if it had been written that way in the first place. Finally, modern C compilers, such as gcc, can perform whole program optimisation, applying interprocedural optimisation to all functions and variables, including statically-linked libraries. -- Martin Dr Martin Ward | Email: [email protected] | http://www.gkc.org.uk G.K.Chesterton site: http://www.gkc.org.uk/gkc | Erdos number: 4
