Maxim Integrated MAX31782 - Manual (Page 188)

MaximIntegrated 20-5
MAX31782 User’s Guide
Revision 0; 8/11
{L/S}CALLsrc {Long/Short}CalltoSubroutine
Description: Performs a call to the subroutine destination specified by src . The CALL instruction uses an 8-bit
immediate src to perform a relative short call (IP +127/-128 words) . The CALL instruction uses a
16-bit immediate src to perform an absolute long CALL to the specified 16-bit address . The PFX[0]
register is used to supply the high byte of a 16-bit immediate address for the absolute long CALL .
Using the optional ‘L’ prefix (i .e ., LCALL) results in an absolute long call and use of the PFX[0]
register . Using the optional ‘S’ prefix (i .e ., SCALL) attempts to generate a relative short call, but is
flagged by the assembler if the destination is out of range . Specifying an internal register src always
produces an absolute CALL to a 16-bit address, thus the ‘L’ and ‘S’ prefixes should not be used .
StatusFlags: None
Operation: @++SP ← IP + 1 PUSH
IP ← src Absolute CALL
IP ← IP + src Relative CALL
Encoding: 15 0
f011 1101 ssss ssss
Example(s): CALL label1 ; relative call to label1 (must be within IP +127/ -
; 128 address range)
CALL label1 ; absolute call to label1 = 0120h
; MOVE PFX[0], #01h
; CALL #20h .
CALL DP[0] ; DP[0] holds 16-bit address of subroutine
LCALL label1 ; label=0120h and is relative to this instruction
; absolute call is forced by use of ‘L’ prefix
; MOVE PFX[0], #01h
; CALL #20h
SCALL label1 ; relative offset for label1 calculated and used
; if label1 is not relative, assembler will generate an error
SCALL #10h ; relative offset of #10h is used directly by the CALL