Typewriter User Manual

5- 26 MC68340 USER’S MANUAL MOTOROLA
5.3.3.7 BINARY-CODED DECIMAL (BCD) INSTRUCTIONS. Five instructions support
operations on BCD numbers. The arithmetic operations on packed BCD numbers are add
decimal with extend (ABCD), subtract decimal with extend (SBCD), and negate decimal
with extend (NBCD). Table 5-9 is a summary of the BCD operations.
Table 5-9. Binary-Coded Decimal Operations
Instruction
Operand
Syntax Operand Size Operation
ABCD Dn, Dn
– (An), – (An)
8
8
Source
10
+ Destination
10
+ X ⇒ Destination
NBCD 〈ea〉 8
8
0 – Destination
10
– X ⇒ Destination
SBCD Dn, Dn
– (An), – (An)
8
8
Destination
10
– Source
10
– X ⇒ Destination
5.3.3.8 PROGRAM CONTROL INSTRUCTIONS. A set of subroutine call and return
instructions and conditional and unconditional branch instructions perform program control
operations. Table 5-10 summarizes these instructions.
Table 5-10. Program Control Operations
Instruction
Operand
Syntax Operand Size Operation
Conditional
Bcc 〈label〉 8, 16, 32 If condition true, then PC + d ⇒ PC
DBcc Dn , 〈label〉 16 If condition false, then Dn – 1 ⇒ PC;
if Dn ≠ (– 1), then PC + d ⇒ PC
Scc 〈ea〉 8 If condition true, then destination bits are set to 1;
else destination bits are cleared to 0
Unconditional
BRA 〈label〉 8, 16, 32 PC + d ⇒ PC
BSR 〈label〉 8, 16, 32 SP – 4 ⇒ SP; PC ⇒ (SP); PC + d ⇒ PC
JMP 〈ea〉 none Destination ⇒ PC
JSR 〈ea〉 none SP – 4 ⇒ SP; PC ⇒ (SP); destination ⇒ PC
NOP none none PC + 2 ⇒ PC
Returns
RTD #〈d〉 16 (SP) ⇒ PC; SP + 4 + d ⇒ SP
RTR none none (SP) ⇒ CCR; SP + 2 ⇒ SP; (SP) ⇒ PC; SP + 4 ⇒
SP
RTS none none (SP) ⇒ PC; SP + 4 ⇒ SP
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