Board.KolibriOS.org

integer_division:
; eax = eax/ebx
   test   ebx,ebx
   jnz   @f
   inc   ebx
@@:
   xor   edx,edx
   div   ebx
   shl   edx,1
   cmp   ebx,edx
   jb   @f
   inc   eax
;@@:
   ret

sqrt: ;24 code (not comments) strings
;in: eax-number; out: ebx-result of fullnumber sqrt,
; if eax wasn't changed, ebx is ideal result, else:
; ecx-(bigger-ideal), eax-(ideal-smaller);
; result is bigger than floatpoint if ecx<eax, else smaller;
; to find percentage, b=ecx/(ecx+eax), s=eax/(ecx+eax):
; ((b>>0)=>b is nearly to ideal, for s is same; always<1)
cmp eax,0
jne @f
    xor ebx,ebx
    ret
@@:
mov ebx,-1
xor ecx,ecx
@@:
    add ebx,2
    add ecx,ebx
cmp ecx,eax
je @f ; we don't need to find nearly result, ecx is this.
jb @b
;now: ecx-bigger square, (ecx-ebx)-smaller, eax-ideal;
;need: check, what square mostly near to input number.
    sub ecx,eax
    mov eax,ebx
    sub eax,ecx ; eax=ebx-(ecx-eax)=eax-(ecx-ebx)=ideal-smaller.
    cmp ecx,eax ; cmp(bigger-ideal,ideal-smaller).
    jb @f ; ecx mostly near.
    sub ebx,2 ; it will be incremented soon, so lets annihilate this.
;crushed: eax; now: ecx,eax-see header.
@@: ; ecx is better
    inc ebx
shr ebx,1
ret

{Converts a cardinal to string at the buffer location, returning the new
 buffer position. Note: Only supports numbers up to 2^31.}
function CardinalToStrBuf(ACardinal: Cardinal; APBuffer: PAnsiChar): PAnsiChar;
asm
  {On entry: eax = ACardinal, edx = ABuffer}
  push edi
  mov edi, edx                //Pointer to the first character in edi
  {Calculate leading digit: divide the number by 1e9}
  add eax, 1                  //Increment the number
  mov edx, $89705F41          //1e9 reciprocal
  mul edx                     //Multplying with reciprocal
  shr eax, 30                 //Save fraction bits
  mov ecx, edx                //First digit in bits <31:29>
  and edx, $1FFFFFFF          //Filter fraction part edx<28:0>
  shr ecx, 29                 //Get leading digit into accumulator
  lea edx, [edx + 4 * edx]    //Calculate ...
  add edx, eax                //... 5*fraction
  mov eax, ecx                //Copy leading digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store digit out to memory
  {Calculate digit #2}
  mov eax, edx                //Point format such that 1.0 = 2^28
  cmp ecx, 1                  //Any non-zero digit yet ?
  sbb edi, -1                 //Yes->increment ptr, No->keep old ptr
  shr eax, 28                 //Next digit
  and edx, $0fffffff          //Fraction part edx<27:0>
  or ecx, eax                 //Accumulate next digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store digit out to memory
  {Calculate digit #3}
  lea eax, [edx * 4 + edx]    //5*fraction, new digit eax<31:27>
  lea edx, [edx * 4 + edx]    //5*fraction, new fraction edx<26:0>
  cmp ecx, 1                  //Any non-zero digit yet ?
  sbb edi, -1                 //Yes->increment ptr, No->keep old ptr
  shr eax, 27                 //Next digit
  and edx, $07ffffff          //Fraction part
  or ecx, eax                 //Accumulate next digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store digit out to memory
  {Calculate digit #4}
  lea eax, [edx * 4 + edx]    //5*fraction, new digit eax<31:26>
  lea edx, [edx * 4 + edx]    //5*fraction, new fraction edx<25:0>
  cmp ecx, 1                  //Any non-zero digit yet ?
  sbb edi, -1                 //Yes->increment ptr, No->keep old ptr
  shr eax, 26                 //Next digit
  and edx, $03ffffff          //Fraction part
  or ecx, eax                 //Accumulate next digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store digit out to memory
  {Calculate digit #5}
  lea eax, [edx * 4 + edx]    //5*fraction, new digit eax<31:25>
  lea edx, [edx * 4 + edx]    //5*fraction, new fraction edx<24:0>
  cmp ecx, 1                  //Any non-zero digit yet ?
  sbb edi, -1                 //Yes->increment ptr, No->keep old ptr
  shr eax, 25                 //Next digit
  and edx, $01ffffff          //Fraction part
  or ecx, eax                 //Accumulate next digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store digit out to memory
  {Calculate digit #6}
  lea eax, [edx * 4 + edx]    //5*fraction, new digit eax<31:24>
  lea edx, [edx * 4 + edx]    //5*fraction, new fraction edx<23:0>
  cmp ecx, 1                  //Any non-zero digit yet ?
  sbb edi, -1                 //Yes->increment ptr, No->keep old ptr
  shr eax, 24                 //Next digit
  and edx, $00ffffff          //Fraction part
  or ecx, eax                 //Accumulate next digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store digit out to memory
  {Calculate digit #7}
  lea eax, [edx * 4 + edx]    //5*fraction, new digit eax<31:23>
  lea edx, [edx * 4 + edx]    //5*fraction, new fraction edx<31:23>
  cmp ecx, 1                  //Any non-zero digit yet ?
  sbb edi, -1                 //Yes->increment ptr, No->keep old ptr
  shr eax, 23                 //Next digit
  and edx, $007fffff          //Fraction part
  or ecx, eax                 //Accumulate next digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store digit out to memory
  {Calculate digit #8}
  lea eax, [edx * 4 + edx]    //5*fraction, new digit eax<31:22>
  lea edx, [edx * 4 + edx]    //5*fraction, new fraction edx<22:0>
  cmp ecx, 1                  //Any non-zero digit yet ?
  sbb edi, -1                 //Yes->increment ptr, No->keep old ptr
  shr eax, 22                 //Next digit
  and edx, $003fffff          //Fraction part
  or ecx, eax                 //Accumulate next digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store digit out to memory
  {Calculate digit #9}
  lea eax, [edx * 4 + edx]    //5*fraction, new digit eax<31:21>
  lea edx, [edx * 4 + edx]    //5*fraction, new fraction edx<21:0>
  cmp ecx, 1                  //Any non-zero digit yet ?
  sbb edi, -1                 //Yes->increment ptr, No->keep old ptr
  shr eax, 21                 //Next digit
  and edx, $001fffff          //Fraction part
  or ecx, eax                 //Accumulate next digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store digit out to memory
  {Calculate digit #10}
  lea eax, [edx * 4 + edx]    //5*fraction, new digit eax<31:20>
  cmp ecx, 1                  //Any-non-zero digit yet ?
  sbb edi, -1                 //Yes->increment ptr, No->keep old ptr
  shr eax, 20                 //Next digit
  or eax, '0'                 //Convert digit to ASCII
  mov [edi], al               //Store last digit and end marker out to memory
  {Return a pointer to the next character}
  lea eax, [edi + 1]
  {Restore edi}
  pop edi
end;