No one should use the AT&T syntax (2021)

Post by rep_lodsb » Mon, Jun 10, 2024, 9:46 AM UTC

m463 wrote: post #94

amluto wrote: post #39

I think there are two legitimate reasons to use Intel syntax: 1. It matches the manual. AMD and Intel’s manuals agree about operand order, and IMO there is no justification whatsoever for an assembly syntax to fail to match the documentation. This is especially true for 3-address instructions and for two-input instructions like CMP. All these arguments about mathematical notation or linguistics are nonsense in my boo…

I learned ibm 370 assembly first, PDP-11 assembly second, then I think Z80. I found them to be very regular and understandable. So when I encountered intel chips and their assembly syntax, I disliked them. So about that time I switched to higher level languages. Are there still chips left have a nice orthogonal assembly language? I vaguely recall 68k being orthogonal too.

    ADD  A,B     ;8 bit add, B to A
    ADD  HL,BC   ;16 bit add, BC to HL
    ADD  B,A     ;invalid! destination can only be A or HL

    ADC  A,B     ;add with carry
    SBC  A,B     ;subtract with carry
    SUB  B       ;subtract (A is implicit, same for AND,OR,XOR)

    LD   A,(HL)  ;load A from memory at HL
    LD   B,(HL)  ;load B from HL
    LD   A,(DE)  ;load A from DE
    LD   B,(DE)  ;invalid! must be reg=A or mem=(HL)

    LD   A,(var)  ;load A from variable
    LD   HL,(var) ;load HL from variable
    LD   DE,(var) ;extra opcode byte, 4 cycles slower
    LD   B,(var)  ;invalid! must be A or register pair

    JP   (HL)     ;load PC with contents of HL register, NOT MEMORY!

    EX   DE,HL   ;exchange DE with HL (no other registers allowed)
    EX   HL,(SP) ;exchange HL with top of stack (no other reg,mem allowed)
    EX   AF,AF'  ;wtf were they thinking?
    EXX          ;should be EX BCDEHL,BCDEHL' for consistency :)

Post by LinAGKar » Mon, Jun 10, 2024, 1:11 PM UTC

kleton wrote: post #53

kstenerud wrote: post #14

> Putting the destination operand first emphasizes the site of mutation. This doesn't make any more convincing an argument than the "linguistic" and "consistency" arguments he shot down earlier. Why should putting the mutated argument first emphasize it any more than putting it second? If you order things the same way every time, people will implicitly know which one is the mutated argument because that's how the lan…

> [src, dst] is closer to human language In English, but not Telugu.

Post by vidarh » Mon, Jun 10, 2024, 2:42 PM UTC

pclmulqdq wrote: post #103

vidarh wrote: post #98

Earlier quoted context omitted.

How many of them have experience with other assembly languages? For me, it was exposure to M68k that made Intel syntax seem absolutely awful. AT&T syntax is also awful, but at least the operand order is the way that I'm (still) more used to.

Many of the assembly writers have exposure across platforms, but often with modern assemblers whose syntax tracks Intel syntax more closely. I don't know why 68000 is so popular here (maybe people on HN learned it in school?), but you're far more likely to be writing ARM assembly or these days RISC-V assembly than writing for an antiquated core like the 68000. Believe it or not, outside the x86 world, Intel-style syn…

Post by librasteve » Mon, Jun 10, 2024, 8:46 PM UTC

tmtvl wrote: post #67

kazinator wrote: post #20

OK, so renaming a file should be: $ mv new-name.txt old-name.txt I defer to the blogger's superior UX expertise!

Eh, there's examples of every permutation: ;; Lisp (setf a (xor b c)) ;; Kanren ;; Unification instead of mutation. ;; Therefore these are equivalent: (== a (xor b c)) (== (xor b c) a) # Contrived untested Raku example $b ^^ $c ==> my $a; % Amberjack b xor c -> a // Java var a = b ^ c;

  my $b = 42;
  my $c = False; 

  $b ^^ $c ==> my $a; 
  say $a;    #[42]

Post by musicale » Tue, Jun 11, 2024, 6:58 AM UTC

rep_lodsb wrote: post #102

m463 wrote: post #94

Earlier quoted context omitted.

I learned ibm 370 assembly first, PDP-11 assembly second, then I think Z80. I found them to be very regular and understandable. So when I encountered intel chips and their assembly syntax, I disliked them. So about that time I switched to higher level languages. Are there still chips left have a nice orthogonal assembly language? I vaguely recall 68k being orthogonal too.

Sorry, but Z80 being "regular and understandable"? ADD A,B ;8 bit add, B to A ADD HL,BC ;16 bit add, BC to HL ADD B,A ;invalid! destination can only be A or HL ADC A,B ;add with carry SBC A,B ;subtract with carry SUB B ;subtract (A is implicit, same for AND,OR,XOR) LD A,(HL) ;load A from memory at HL LD B,(HL) ;load B from HL LD A,(DE) ;load A from DE LD B,(DE) ;invalid! must be reg=A or mem=(HL) LD A,(var) ;load A f…