[fpc-devel] succ(byte)

[Carsten Bager]

Here is output from the 2.4.5 Compiler and the 2.62 compiler. of the following program 
compiled the same way.

It has always been possible to eliminate runtime checking when incrementing a byte/word in 
this way (if one wants the byte to roll over).
This is not possible with the 2.6.2 compiler. Is there a reason for this.

Carsten


program test_arm9;

Var
  b:byte;
begin
  b:=byte(succ(b));
end.



Free Pascal Compiler version 2.4.5 [2012/06/19] for arm
# [6] b:=byte(succ(b));
        ldr     r0,.Lj5
        ldrb    r0,[r0]
        add     r0,r0,#1
        and     r0,r0,#255
        ldr     r1,.Lj5
        strb    r0,[r1]
        .stabn 68,0,7,.Ll3 - main



Free Pascal Compiler version 2.6.2 [2013/07/16] for arm
# [6] b:=byte(succ(b));
        ldr     r0,.Lj5
        ldrb    r0,[r0]
        adds    r1,r0,#1
        bcc     .Lj6
        bl      FPC_OVERFLOW
.Lj6:
        mov     r0,r1
        add     r0,r0,#0
        cmp     r0,#255
        bls     .Lj7
        bl      FPC_RANGEERROR
.Lj7:
        and     r0,r1,#255
        ldr     r1,.Lj5
        strb    r0,[r1]
        .stabn 68,0,7,_$TEST_ARM9$_Ll3 - main