UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 95

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

NEC assembler (RA78K4), the register operation code generated when the A, X, B, C, AX and BC registers are described by
those names is determined by the assembler RSS pseudo-instruction.
relevant instruction (see example below).
(2) Operation code generation method with RA78K4
Registers used other than those mentioned above are always the same irrespective of the value of the RSS bit. With the
When the RSS bit is set or reset, an RSS pseudo-instruction must be written immediately before (or immediately after) the
<Program example>
• With RA78K4, if there is an instruction with the same function as an instruction for which A or AX is directly entered in
• When RSS is set to 0
• When RSS is set to 1
Example The function is the same when B is used as r in a MOV A,r instruction, and when A is used as r and B is used
the operand column of the instruction operation list, the operation code for which A or AX is directly entered in the operand
column is generated first.
RSS 0
CLR1 PSWL.5
MOV B, A
RSS 1
SET1 PSWL.5
MOV B, A
as r’ in a MOVr,r’ instruction, and the same code (MOV,A,B) is used in the assembler source program. In this
case, RA78K4 generates code equivalent to the MOV A, r instruction.
; RSS pseudo-instruction
; This code is equivalent to “MOV R3, R1”.
; RSS pseudo-instruction
; This code is equivalent to “MOV R7, R5”.
CHAPTER 3 CPU ARCHITECTURE
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