Difference between revisions of "PM Opc CMP16"

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(Examples)
m
Line 79: Line 79:
 
  ;
 
  ;
 
  ; Sc2 = Source 2
 
  ; Sc2 = Source 2
  ; Sc = Source
+
  ; Sc = Source
; Ds = Result is discarded
 
 
   
 
   
  Ds = Sc2 - Sc
+
  (discarded) = Sc2 - Sc
  
 
=== Description ===
 
=== Description ===
  
16-Bits Source subtracts to the 16-Bits 2nd Source, Output is discarded.
+
"16-Bits Source 2" subtracts with "16-Bits Source", result is discarded.
  
 
This instruction is used to compare values.
 
This instruction is used to compare values.

Revision as of 19:16, 17 April 2009

CMP = Compare (16-Bits)

Hex Mnemonic Cycles
D4 nn nn CMP BA, #nnnn 12
D5 nn nn CMP HL, #nnnn 12
D6 nn nn CMP X, #nnnn 12
D7 nn nn CMP Y, #nnnn 12
CF 6C nn nn CMP SP, #nnnn 16
CF 18 CMP BA, BA 16
CF 19 CMP BA, HL 16
CF 1A CMP BA, X 16
CF 1B CMP BA, Y 16
CF 38 CMP HL, BA 16
CF 39 CMP HL, HL 16
CF 3A CMP HL, X 16
CF 3B CMP HL, Y 16
CF 5C CMP SP, BA 16
CF 5D CMP SP, HL 16

Execute

#nnnn    = Immediate unsigned 16-Bits
BA       = Register BA: (B shl 8) or A
HL       = Register HL: (H shl 8) or L
X        = Register X
Y        = Register Y
SP       = Register SP (Stack Pointer)
; CMP Sc2, Sc
;
; Sc2 = Source 2
; Sc  = Source

(discarded) = Sc2 - Sc

Description

"16-Bits Source 2" subtracts with "16-Bits Source", result is discarded.

This instruction is used to compare values.

Conditions

Zero: Set when result is 0

Carry: Set when result is < 0

Overflow: Set when result overflow 16-bits signed range (< -32768 OR > 32767)

Sign: Set when 15th bit is 1

Examples

; BA = 0x2EF0
CMP BA, $1337
; BA = 0x2EF0
;      0x1BB9 (0x2EF0 - 0x1337 = 0x(0)1BB9)
; F = (Zero = 0):(Carry = 0):(Overflow=0):(Sign=0)
; HL = 0xBB7E
; BA = 0xCF12
CMP BA, HL
; HL = 0xBB7E
; BA = 0xCF12
;     0xEC6C (0xCF12 - 0xBB7E = 0x(1)EC6C)
; F = (Zero = 0):(Carry = 1):(Overflow=0):(Sign=1)

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