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// $Id: gpsm_dcm_fast_handler.S,v 1.1.1.1 2013/12/11 20:49:20 bcbrock Exp $
/// \file gpsm_dcm_fast_handler.S
/// \brief Assembler support for GPSM_DCM procedures
/// \cond
.nolist
#include "ssx.h"
#include "pmc_dcm.h"
#include "gpsm_dcm.h"
.list
#define GPSM_IC_CONTINUOUS_DATA (PMC_IC_MSG_CC << 4 | GPSM_IC_DATA)
// The gpsm_dcm_write fast handler.
// Register use:
//
// R3 = Entry: void *arg; *arg -> GpsmDcmFast
// R4 = Entry: SsxIrqId irq; irq : constant
// R5 = Entry: int priority; priority -> data
// R6 = data_pointer
// R7 = remaining_size
// CR = <condition>
// LR = <return address>
// No other registers can be used, other than SPRG
.global_function gpsm_dcm_fast_write
gpsm_dcm_fast_write:
_ssx_irq_status_clear %r4, %r6, %r7 //clear status first
lwz %r6, 0(%r3) //load data pointer
lwz %r7, 4(%r3) //load remaining size
cmpwi %r7, 0 //if size == 0
beq exit_write_handler //exit fast write
cmpwi %r7, 1 //if size == 1
beq load_one_byte //load only one byte
lhz %r5, 0(%r6) //otherwise load two bytes
addi %r6, %r6, 2 //data pointer+2
addi %r7, %r7,-2 //remaining size-2
b form_and_send_packet //then form and send packet
load_one_byte:
lbz %r5, 0(%r6) //load one byte from buffer
addi %r6, %r6, 1 //data pointer+1
addi %r7, %r7,-1 //remaining size-1
form_and_send_packet:
stw %r6, 0(%r3) //store updated data pointer
stw %r7, 4(%r3) //store updated remaining size
lis %r6, GPSM_IC_CONTINUOUS_DATA //load cmd code to upper bits
or %r5, %r5, %r6 //load data into lower bits
slwi %r5, %r5, 8 //packet<<8 to give ecc field
_stwi %r5, %r7, PMC_INTCHP_MSG_WDATA //send packet
blr //return
exit_write_handler:
bl __ssx_irq_fast2full //convert fast to full irq handler
_ssx_irq_disable %r4, %r6, %r7 //disable this irq
addi %r3, %r3, 8 //argument pointer to semaphore
bl ssx_semaphore_post //post to that semaphore
b __ssx_irq_full_mode_exit //exit
.epilogue gpsm_dcm_fast_write
// The gpsm_dcm_read fast handler.
// Register use:
//
// R3 = Entry: void *arg; *arg -> GpsmDcmFast(data,size,semaphore)
// R4 = Entry: SsxIrqId irq; irq : constant
// R5 = Entry: int priority; priority -> data
// R6 = data_pointer
// R7 = remaining_size
// CR = <condition>
// LR = <return address>
// No other registers can be used, other than SPRG
.global_function gpsm_dcm_fast_read
gpsm_dcm_fast_read:
_ssx_irq_status_clear %r4, %r6, %r7 //clear status first
lwz %r7, 4(%r3) //load remaining size
cmpwi %r7, 0 //if size == 0
beq exit_read_handler //then exit fast read
_lwzi %r6, %r7, PMC_INTCHP_MSG_RDATA //receive packet
extrwi %r5, %r6, 16, 8 //extract data to r5
extrwi %r6, %r6, 8, 0 //extract cmd code to r6
li %r7, GPSM_IC_CONTINUOUS_DATA //designated cmd code to r7
cmpw %r6, %r7 //compare and check cmd code
bne panic_read_packet //panic on wrong cmd code
lwz %r6, 0(%r3) //load data pointer
lwz %r7, 4(%r3) //load remaining size
cmpwi %r7, 1 //if only one byte left
beq store_one_byte //then store only one byte
sth %r5, 0(%r6) //otherwise store two bytes to buf
addi %r6, %r6, 2 //data pointer+2
addi %r7, %r7,-2 //remaining size-2
b check_read_status //check read status
store_one_byte:
stb %r5, 0(%r6) //store one byte to buf
addi %r6, %r6, 1 //data pointer+1
addi %r7, %r7,-1 //remaining size-1
check_read_status:
stw %r6, 0(%r3) //store updated data pointer
stw %r7, 4(%r3) //store updated remaining size
cmpwi %r7, 0 //if size == 0
beq exit_read_handler //then terminate fast read
blr //return if still data left
exit_read_handler:
bl __ssx_irq_fast2full //convert fast to full irq handler
_ssx_irq_disable %r4, %r6, %r7 //disable this irq
addi %r3, %r3, 8 //argument pointer to semaphore
bl ssx_semaphore_post //post to that semaphore
b __ssx_irq_full_mode_exit //exit
panic_read_packet:
SSX_PANIC(GPSM_DCM_READ_NOT_WRITE_DATA) //PANIC if cmd code is wrong
.epilogue gpsm_dcm_fast_read
/// \endcond
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