<!-- This defines DRAFT instructions described in SV -->

<!-- This defines instructions that store from a register to RAM -->
<!-- Effective Address is always RA, and the usual EA is stored late in RA -->

# Store Byte with Update

D-Form

* stbup RS,D(RA)

Pseudo-code:

    EA <- (RA) + EXTS(D)
    ea <- (RA)
    MEM(ea, 1) <- (RS)[XLEN-8:XLEN-1]
    RA <- EA

Description:

    Let the effective address (EA) be the sum (RA)+ D.
    (RS)[56:63] are stored into the byte in storage addressed
    by EA. 

    EA is placed into register RA.

    If RA=0, the instruction form is invalid.

Special Registers Altered:

    None

# Store Byte with Update Indexed

X-Form

* stbupx RS,RA,RB

Pseudo-code:

    EA <- (RA) + (RB)
    ea <- (RA)
    MEM(ea, 1) <- (RS)[XLEN-8:XLEN-1]
    RA <- EA

Description:

    Let the effective address (EA) be the sum (RA)+ (RB).
    (RS)[56:63] are stored into the byte in storage addressed
    by EA.

    EA is placed into register RA.

    If RA=0, the instruction form is invalid.

Special Registers Altered:

    None

# Store Halfword with Update

D-Form

* sthup RS,D(RA)

Pseudo-code:

    EA <- (RA) + EXTS(D)
    ea <- (RA)
    MEM(ea, 2) <- (RS)[XLEN-16:XLEN-1]
    RA <- EA

Special Registers Altered:

    None

# Store Halfword with Update Indexed

X-Form

* sthupx RS,RA,RB

Pseudo-code:

    EA <- (RA) + (RB)
    ea <- (RA)
    MEM(ea, 2) <- (RS)[XLEN-16:XLEN-1]
    RA <- EA

Special Registers Altered:

    None

# Store Word with Update

D-Form

* stwup RS,D(RA)

Pseudo-code:

    EA <- (RA) + EXTS(D)
    ea <- (RA)
    MEM(ea, 4) <- (RS)[XLEN-32:XLEN-1]
    RA <- EA

Special Registers Altered:

    None

# Store Word with Update Indexed

X-Form

* stwupx RS,RA,RB

Pseudo-code:

    EA <- (RA) + (RB)
    ea <- (RA)
    MEM(ea, 4) <- (RS)[XLEN-32:XLEN-1]
    RA <- EA

Special Registers Altered:

    None

# Store Doubleword with Update

DS-Form

* stdup RS,DS(RA)

Pseudo-code:

    EA <- (RA) + EXTS(DS || 0b00)
    ea <- (RA)
    MEM(ea, 8) <- (RS)
    RA <- EA

Special Registers Altered:

    None

# Store Doubleword with Update Indexed

X-Form

* stdupx RS,RA,RB

Pseudo-code:

    EA <- (RA) + (RB)
    ea <- (RA)
    MEM(ea, 8) <- (RS)
    RA <- EA

Special Registers Altered:

    None