Rainbow Electronics AT89C2051 - Manual (Page 10)

Microcontroller
5-56
Table 4. Compare Modifiers
Notes: 1. These instructions must immediately follow a CMP instruction.
2. NOT instruction is used to implement explicit NE.
Table 5. Jump Instructions
Note: 1. Switch table format: addr1, value1, addr2, value2, ... 0, default addr
Table 6. Stack Manipulation Instructions
Note: 1. Explicit POP instruction are not required since various addressing modes use and remove the top item on stack.
Name Description
LT ACC = 1 if less than (signed)
LE ACC = 1 if less than or equal (signed)
GT ACC = 1 if greater than (signed)
GE ACC = 1 if greater than of equal (signed)
ULT ACC = 1 if lower than (unsigned)
ULE ACC = 1 if lower than or same (unsigned)
UGT ACC = 1 if higher than (unsigned)
UGE ACC = 1 if higher than or same (unsigned)
Name Description
JMP Long jump (16-bit absolute)
JZ Long jump if ACC=0 (16-bit absolute)
JNZ Long jump if ACC!=0 (16-bit absolute)
SJMP Short jump (8-bit PC offset)
SJZ Short jump if ACC=0 (8-bit PC offset)
SJNZ Short jump if ACC!=0 (8-bit PC offset)
IJMP Indirect jump (Address in ACC)
SWITCH Jump through switch table (ACC=value, INDEX=table)
Name Description
CALL Call subroutine (16-bit absolute address)
RET Return from subroutine
ALLOC Allocate space on stack (8-bit value)
FREE Release space on stack (8-bit value)
PUSHA Push ACC on stack
PUSHI Push INDEX on stack
TAS Copy ACC to SP
TSA Copy SP to ACC