mcf5282 Freescale Semiconductor, Inc, mcf5282 Datasheet - Page 96

• Manufacturer Part Number: mcf5282
• Manufacturer: Freescale Semiconductor, Inc

Enhanced Multiply-Accumulate Unit (EMAC)
3-18
/* perform the multiply */
product[63:0] = operandY[31:0] * operandX[31:0]
/* check for product overflow */
if (product[63:40] != 0x0000_00)
/* zero-fill to 48 bits before performing any scaling */
/* scale product before combining with accumulator */
switch (SF)
{
}
/* combine with accumulator */
if (MACSR.PAVn == 0)
/* check for accumulation overflow */
if (accumulationOverflow == 1)
}
else {operandY[31:0] = Ry[31:0]
}
then {
}
then {if (inst == MSAC)
}
then {MACSR.PAVn = 1
case 0:
case 1:
case 2:
case 3:
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3
break;
product[40:0] = {product[39:0], 0}
break;
break;
product[39:0] = {0, product[39:1]}
break;
product[47:40] = 0
operandX[31:0] = Rx[31:0]
MACSR.PAVn = 1
MACSR.V = 1
if (inst == MSAC and and
MACSR.V = 1
if (inst == MSAC and and
then operandX[31:0] = {0x0000, Rx[31:16]}
else operandX[31:0] = {0x0000, Rx[15:0]}
then result[47:0] = 0x0000_0000_0000
else if (MACSR.OMC == 1)
then result[47:0] = ACCx[47:0] - product[47:0]
else result[47:0] = ACCx[47:0] + product[47:0]
then result[47:0] = 0x0000_0000_0000
else if (MACSR.OMC == 1)
/* 2-bit scale factor */
/* no scaling specified */
/* SF = “<< 1” */
/* reserved encoding */
/* SF = “>> 1” */
/* product overflow */
then /* overflowed MAC,
then /* overflowed MAC,
result[47:0] = 0xffff_ffff_ffff
saturationMode enabled */
saturationMode enabled */
/* zero-fill upper byte */
MACSR.OMC == 1)
MACSR.OMC == 1)
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