Zilog Z8F0130 Manual do Utilizador descarregar pdf (Página 123)

eZ8

™

CPU Core

User Manual

UM012820-0810 BTJNZ Instruction

108

causes a Program Counter jump to occur because bit 5 of Working Regis-

ter R7 passes the test for a 1. The next instruction executed after the

BTJNZ is the LD instruction. The eZ8 CPU assembler automatically cal

culates the appropriate displacement value of 01h, allowing the Program

Counter to skip the one byte HALT instruction and jump to the NEXT

label that identifies the LD instruction address. The flags are unaffected.

If Working Register R7 contains the value A5h, and register A5h contains

the value

20h (00100000b), the BTJNZ instruction that begins the fol-

lowing code segment:

It does not cause a Program Counter jump to occur because bit 3 of Regis-

ter A5h fails the test for a 1. The next instruction executed after the

BTJNZ is the HALT instruction. The flags are unaffected.

Assembly Code Object Code

BTJNZ 5, r7, NEXT F6 D7 01

HALT 7F

NEXT: This label is not assembled, but used by the

assembler to identify the destination address (the

address of the next instruction).

LD r0, @r2 E3 02

Assembly Code Object Code

BTJNZ 3, @r7, NEXT F7 B7 01

HALT 7F

NEXT: This label is not assembled, but used by the

assembler to identify the destination address

(the address of the next instruction).

LD r0, @r2 E3 02

1 2 ... 118 119 120 121 122 123 124 125 126 127 128 ... 313 314

Sem comentários

Zilog Z8F0130 Manual do Utilizador Página 123