411 REFERENCE · Wikibooks
Oberon/ETH Oberon/Cast
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
PROCEDURE Cast(VAR in:ARRAY OF REAL; VAR out: ARRAY OF INTEGER);
CODE {SYSTEM.i386, SYSTEM.FPU}
MOV EDI, 8[EBP] ; dest = ADR(out)
MOV ECX, 12[EBP] ; count = LEN(out)
MOV ESI, 16[EBP] ; source = ADR(in)
CMP ECX, 20[EBP]
JGE Ok
PUSH 99 ; LEN(in) > LEN(out) then TRAP(99)
INT 3
Ok:
SUB ESP, 8 ; change FPU rounding to "chop"
FSTCW 0[ESP]
WAIT
MOV EBX, 0[ESP]
OR EBX, 0400H ; clear bit 10,11 (chop/truncate toward zero)
MOV 4[ESP], EBX
FLDCW 4[ESP]
JMP Check
Loop:
DEC ECX
FLD DWORD [ESI][ECX*4] ; in: REAL
FISTP WORD [EDI][ECX*2] ; out: INTEGER
WAIT
Check:
CMP ECX, 0
JG Loop
FLDCW 0[ESP] ; restore original FPU configuration
ADD ESP, 8
END Cast;
If in: ARRAY OF LONGREAL then use
FLD QWORD [ESI][ECX*8] ; in: LONGREAL
If out: ARRAY OF LONGINT then use
FISTP DWORD [ESI][ECX*4] ; out: LONGINT