|59h||MT$FNGT||floating point negation|
|Input||X register - address of the floating-point register to be negated.|
|Output||- none -|
Toggles the sign of the register pointed to by X.
Note that as this routine operates on a register, it assumes a mantissa length of 7 bytes. To negate a normal BCD number, X should point to the byte below the first byte of the number in memory.
Registers B and X are preserved.
To change the sign of the accumulator, execute the following code:
LDX #MTT_AMAN OS MT$FNGTand to negate the constant 202.88:
FP_CONST: DB 0,0,0,80h,28h,20h ;mantissa DB 2 ;exponent DB 0 ;sign LDX #FP_CONST-1 OS MT$FNGT
|Errors||- none -|