[DRAFT] Multiply and Add Extended Doubleword Unsigned

VA-Form

  • maddedu RT,RA,RB,RC

Pseudo-code:

<!-- SVP64: RA,RB,RC,RT have EXTRA2, RS as below
<!-- bit 8 of EXTRA is set  : RS.[s|v]=RT.[s|v]+MAXVL
<!-- bit 8 of EXTRA is clear: RS.[s|v]=RC.[s|v]
prod[0:2*XLEN-1] <- (RA) * (RB)
sum[0:2*XLEN-1] <- ([0] * XLEN || (RC)) + prod
RT <- sum[XLEN:2*XLEN-1]
RS <- sum[0:XLEN-1]

Special Registers Altered:

None

[DRAFT] Multiply and Add Extended Doubleword Unsigned Signed

VA-Form

  • maddedus RT,RA,RB,RC

Pseudo-code:

<!-- SVP64: RA,RB,RC,RT have EXTRA2, RS as below
<!-- bit 8 of EXTRA is set  : RS.[s|v]=RT.[s|v]+MAXVL
<!-- bit 8 of EXTRA is clear: RS.[s|v]=RC.[s|v]
<!-- no MULUS, so do it manually -->
prod[0:XLEN*2-1] <- [0] * (XLEN * 2)
if (RB)[0] != 0 then
    prod[0:XLEN*2-1] <- -((RA) * -(RB))
else
    prod[0:XLEN*2-1] <- (RA) * (RB)
<!-- no EXTS2XL, so do it manually -->
sum[0:XLEN*2-1] <- prod + (EXTSXL((RC)[0], 1) || (RC))
RT <- sum[XLEN:2*XLEN-1]
RS <- sum[0:XLEN-1]

Special Registers Altered:

None

[DRAFT] Divide/Modulo Double-width Doubleword Unsigned

VA-Form

  • divmod2du RT,RA,RB,RC

Pseudo-code:

<!-- SVP64: RA,RB,RC,RT have EXTRA2, RS as below
<!-- bit 8 of EXTRA is set  : RS.[s|v]=RT.[s|v]+MAXVL
<!-- bit 8 of EXTRA is clear: RS.[s|v]=RC.[s|v]
if ((RC) <u (RB)) & ((RB) != [0]*XLEN) then
    dividend[0:(XLEN*2)-1] <- (RC) || (RA)
    divisor[0:(XLEN*2)-1] <- [0]*XLEN || (RB)
    result <- dividend / divisor
    modulo <- dividend % divisor
    RT <- result[XLEN:(XLEN*2)-1]
    RS <- modulo[XLEN:(XLEN*2)-1]
    overflow <- 0
else
    overflow <- 1
    RT <- [1]*XLEN
    RS <- [0]*XLEN

Special Registers Altered:

None

[DRAFT] Double-width Shift Left Doubleword

VA2-Form

  • dsld RT,RA,RB,RC (Rc=0)
  • dsld. RT,RA,RB,RC (Rc=1)

Pseudo-code:

n <- (RB)[58:63]
v <- ROTL64((RA), n)
mask <- MASK(0, 63-n)
RT <- (v[0:63] & mask) | ((RC) & ¬mask)
RS <- v[0:63] & ¬mask
overflow <- 0
if RS != [0]*64 then
    overflow <- 1

Special Registers Altered:

CR0                    (if Rc=1)

[DRAFT] Double-width Shift Right Doubleword

VA2-Form

  • dsrd RT,RA,RB,RC (Rc=0)
  • dsrd. RT,RA,RB,RC (Rc=1)

Pseudo-code:

n <- (RB)[58:63]
v <- ROTL64((RA), 64-n)
mask <- MASK(n, 63)
RT <- (v[0:63] & mask) | ((RC) & ¬mask)
RS <- v[0:63] & ¬mask
overflow <- 0
if RS != [0]*64 then
    overflow <- 1

Special Registers Altered:

CR0                    (if Rc=1)