Renesas Renasas Single-Chip Microcomputer SH7086 Manual de usuario descargar pdf (Pagina 136)

118

3.2 Functions

Chapter 3 Functions

SHift Arithmetic

Shift arithmetic

[ Syntax ]

SHA.size src,dest

[ Related Instructions ] ROLC,RORC,ROT,SHL

SHA

B , W , L

[ Function ]

[ Description Example ]

SHA.B #3,R0L ; Arithmetically shifted left

SHA.B #–3,R0L ; Arithmetically shifted right

SHA.L R1H,R2R0

[ Operation ]

When

src

< 0

When

src

> 0

[ Flag Change ]

UIOBSZDC

[ Selectable src/dest ]

src dest

R0L/R0 R0H/R1 R1L/R2 R1H

/R3 R0L/R0 R0H/R1

R1L/R2 R1H/R3

A0/A0 A1/A1 [A0] [A1] A0/A0 A1/A1 [A0] [A1]

dsp:8[A0] dsp:8[A1] dsp:8[SB] dsp:8[FB] dsp:8[A0] dsp:8[A1] dsp:8[SB] dsp:8[FB]

dsp:16[A0] dsp:16[A1] dsp:16[SB] abs16 dsp:16[A0] dsp:16[A1] dsp:16[SB] abs16

dsp:20[A0] dsp:20[A1] abs20 #IMM

dsp:20[A0] dsp:20[A1] abs20

R2R0 R3R1 A1A0 R2R0

R3R1

A1A0

*1 If

src

is R1H, you cannot choose R1 or R1H for

dest

*2 The range of values that can be taken on is –8 < #IMM < +8. However, you cannot set 0.

*3 You can only specify (.L) for the size specifier (.size). For other

dest

, you can specify (.B) or (.W).

SHA

[ Instruction Code/Number of Cycles ]

Page=

227

MSB dest LSB

overflowing from LSB (MSB) is transferred to the C flag.

• The direction of shift is determined by the sign of

src

. If

src

is positive, bits are shifted left; if negative,

bits are shifted right.

• If

src

is an immediate, the number of shifts is –8 to –1 and +1 to +8. You cannot set values less than

–8, equal to 0, or greater than +8.

• If

src

is a register and you selected (.B) for the size specifier (.size), the number of shifts is –8 to +8.

Although you can set 0, no bits are shifted and no flags are changed. If you set a value less than –8 or

greater than +8, the result of shift is indeterminate.

• If

src

is a register and you selected (.W) or (.L) for the size specifier (.size), the number of shifts is –16

to +16. Although you can set 0, no bits are shifted and no flags are changed. If you set a value less

than –16 or greater than +16, the result of shift is indeterminate.

Flag

Change

Conditions

The flag is set when the operation resulted in MSB changing its state from 1 to 0 or from 0 to 1; otherwise

cleared. However, the flag does not change if you selected (.L) for the size specifier (.size).

S : The flag is set when the operation resulted in MSB = 1; otherwise cleared.

The flag is set when the operation resulted in 0; otherwise cleared. However, the flag is indeterminate if you

selected (.L) for the size specifier (.size).

C : The flag is set when the bit shifted out last is 1; otherwise cleared. However, the flag is indeterminate if you

selected (.L) for the size specifier (.size).

*1 If the number of shifts is 0, no flags are changed.

1 2 ... 131 132 133 134 135 136 137 138 139 140 141 ... 307 308

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