LMIA advanced development kit

This project was developed as a simple development kit for programming and microprogramming the LMIA system.

μASM instruction set

NOP [reg]

No-operation. This wastes one clock cycle

MOV [regA] [regB]

Move value in regA to regB

This operation uses the bus

If regB is LC, no other LC operation can be specified in the same cycle

MVN {[reg] | [const]}

Move the inverse of a value (from register or constant) into register AR.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

MVZ [reg]

Set AR to zero. reg is ignored and only prevalent due to a microcompiler quirk; expect it to be removed in future releases.

Sets flags: Z, N

ADD {[reg] | [const]}

Add value (from register or constant) to register AR.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N, O, C

SUB {[reg] | [const]}

Subtract value (from register or constant) from register AR.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N, O, C

AND {[reg] | [const]}

Perform bitwise AND with given value (from register or constant) and register AR. reg is ignored and only prevalent due to a microcompiler quirk; expect it to be removed in future releases.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N

ORR {[reg] | [const]}

Perform bitwise Or with given value (from register or constant) and register AR.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N

ADN {[reg] | [const]}

Add value (from register or constant) to register AR without updating flags.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

LSL [reg]

Performs a logical shift left of AR. reg is ignored and only prevalent due to a microcompiler quirk; expect it to be removed in future releases.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N, C

BSL [reg]

Performs a logical shift left of AR and HR as if they were one 32-bit register where AR corresponds to the most-significant bits. reg is ignored and only prevalent due to a microcompiler quirk; expect it to be removed in future releases.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N, C

ASR [reg]

Performs an arithmetic shift right on AR. reg is ignored and only prevalent due to a microcompiler quirk; expect it to be removed in future releases.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N, C

BSR [reg]

Performs an arithmetic shift right of AR and HR as if they were one 32-bit register where AR corresponds to the most-significant bits. reg is ignored and only prevalent due to a microcompiler quirk; expect it to be removed in future releases.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N, C

LSR [reg]

Performs a logical shift right of AR. reg is ignored and only prevalent due to a microcompiler quirk; expect it to be removed in future releases.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N, C

ROL [reg]

Performs an arithmetic rotate right on AR. reg is ignored and only prevalent due to a microcompiler quirk; expect it to be removed in future releases.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N, C

BRL [reg]

Performs an arithmetic shift left of AR and HR as if they were one 32-bit register where AR corresponds to the most-significant bits. reg is ignored and only prevalent due to a microcompiler quirk; expect it to be removed in future releases.

This operation uses the bus

If a constant is passed, this operation cannot be parallellized

Sets flags: Z, N, C

LCSET [const]

Set LC to value of constant.

CONST [const]

Set AR to value of cosntant.

This operation cannot be parallelized

INCPC

Increment value in PC by one.

DECLC

Decrement value in LC by one.

CALL [label]

Move value in uPC to uSP (MySPC) and set value in uPC to point to the address of the given label.

RET

Move value in uSP (MySPC) into uPC.

HALT

Stop execution and set value int uPC to 0.

BRA [label]

Perform an unconditional branch to the address of the given label.

BNZ [label]

Branch to address of label if Z-flag is 0.

BRZ [label]

Branch to address of label if Z-flag is 1.

BRN [label]

Branch to address of label if N-flag is 1.

BRC [label]

Branch to address of label if C-flag is 1.

BRO [label]

Branch to address of label if O-flag is 1.

BLS [label]

Branch to address of label if L-flag is 1.

BNC [label]

Branch to address of label if C-flag is 0.

BNO [label]

Branch to address of label if O-flag is 0.

Flags

Flags - aside from L - are set based on ALU operations, so they depend on AR and the BUS. Unless otherwise implied or stated, AR refers to the state/value of AR after an ALU operation.

Z

Set if AR == BUS

N

Set if sign bit in AR is set.

O

Set if sign of AR differs from signs of both AR and BUS before the arithmetic operation.

C

Set if AR is less than or equal to AR before the arithmetic operation.

L

Set if LC == 0.