Format 15: multiple load/store – Samsung S3C2440A User Manual

Page 154

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S3C2440A RISC MICROPROCESSOR

THUMB INSTRUCTION SET

4-33

FORMAT 15: MULTIPLE LOAD/STORE

[7:0] Register List

[10:8] Base Register

[11] Load/Store Bit

0 = Store to memory
1 = Load from memory

15

0

1

14

10

1

0

13

12

11

Rlist

0

L

7

8

Rb

Figure 4-16. Format 15

OPERATION

These instructions allow multiple loading and storing of Lo registers. The THUMB assembler syntax is shown in
the following table.

Table 4-16. The Multiple Load/Store Instructions

L

THUMB assembler

ARM equivalent

Description

0

STMIA Rb!, { Rlist }

STMIA Rb!, { Rlist }

Store the registers specified by Rlist,
starting at the base address in Rb. Write
back the new base address.

1

LDMIA Rb!, { Rlist }

LDMIA Rb!, { Rlist }

Load the registers specified by Rlist, starting
at the base address in Rb. Write back the
new base address.

INSTRUCTION CYCLE TIMES

All instructions in this format have an equivalent ARM instruction as shown in Table 4-16. The instruction cycle
times for the THUMB instruction are identical to that of the equivalent ARM instruction.

EXAMPLES

STMIA

R0!, {R3-R7}

; Store the contents of registers R3-R7 starting

at the address specified in R0, incrementing the

addresses for each word. Write back the updated

value

of

R0.

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