<< Previous | Next >>

LD pd,ps+IY     Load     Rabbit 4000/5000 Instruction

Opcode	Instruction	Operation
--	LD pd,ps+IY	pd = ps + IY
6D 05	LD PW,PW+IY	PW = PW + IY
6D 15	LD PW,PX+IY	PW = PX + IY
6D 25	LD PW,PY+IY	PW = PY + IY
6D 35	LD PW,PZ+IY	PW = PZ + IY
6D 45	LD PX,PW+IY	PX = PW + IY
6D 55	LD PX,PX+IY	PX = PX + IY
6D 65	LD PX,PY+IY	PX = PY + IY
6D 75	LD PX,PZ+IY	PX = PZ + IY
6D 85	LD PY,PW+IY	PY = PW + IY
6D 95	LD PY,PX+IY	PY = PX + IY
6D A5	LD PY,PY+IY	PY = PY + IY
6D B5	LD PY,PZ+IY	PY = PZ + IY
6D C5	LD PZ,PW+IY	PZ = PW + IX
6D D5	LD PZ,PX+IY	PZ = PX + IX
6D E5	LD PZ,PY+IY	PZ = PY + IX
6D F5	LD PZ,PZ+IY	PZ = PZ + IX

Clocks	8-Bit Access	16-Bit Unaligned	16-Bit Aligned
Rabbit 4000	4	n/a	n/a
Rabbit 5000	4	4	2

Flags				ALTD			IOI/IOE
S	Z	L/V	C	F	R	SP	S	D
-	-	-	-		·

Description

Loads pd (any of the 32-bit registers PW, PX, PY or PZ) with the sum of ps (any of PW, PX, PY or PZ) and IY. These instructions cannot be used for general 32-bit arithmetic because the addition depends on the upper two bytes of ps. If the upper two bytes are all ones, then it is 16-bit addition. The following example illustrates this point:

ld PW,0xFFFFFFFF
ld PW,PW+IY            ;yields PW=0xFFFF0000 if IY=1

ld PW,0x7FFFFFFF
ld PW,PW+IY            ;yields PW=0x80000000 if IY=1