malloc selects Flash address for DMA transfers in memtest.c instead of SRAM

Hi,

As i said in the original post, the problem i am facing is that malloc in the memtest.c is going out of the SRAM region and the memory transfers fail.

Below is the line of C-code:

ram_loc = (void*)alt_uncached_malloc (memory_size) ;

memory_base = (int) &ram_loc ;

Fixed Location code (alternatively if i use fixed memory locations within the SRAM region the entire test completes the intended memory and DMA transfers):

memory_base = 0x21c700 ;

memory_end = 0x21cf00 ;

I am also attaching the two logs one using the malloc code(that fails at address outside the SRAM region)

# Memory Test Main Menu

# a: Test RAM

#

# Testing RAM from 0x21FFD0 to 0x2203D0

# -Data bus test passed

# Break key hit

# Simulation stop requested.

-Address bus test failed at address 0x220010# End time: 13:50:26 on Nov 13,2018, Elapsed time: 0:24:23

# Errors: 0, Warnings: 87

and also one with fixed address (all memory test and DMA transfers complete).

# Memory Test Main Menu

# a: Test RAM

#

# Testing RAM from 0x21C700 to 0x21CF00

# -Data bus test passed

# -Address bus test passed

# -Byte and half-word access test passed

# -Testing each bit in memory device. passed

# -Testing memory using DMA.

# Source Address:0x206818 Destination Address:0x206A20

# DMA transfer Src2Mem Done starting At:0x21C700

# DMA transfer Mem2Dest Done starting At:0x21C700

# DMA transfer Src2Mem Done starting At:0x21C900

# DMA transfer Mem2Dest Done starting At:0x21C900

# DMA transfer Src2Mem Done starting At:0x21CB00

# DMA transfer Mem2Dest Done starting At:0x21CB00

# DMA transfer Src2Mem Done starting At:0x21CD00

# DMA transfer Mem2Dest Done starting At:0x21CD00

# passed

# Memory at 0x21C700 Okay

#

I have just added more print statments in the C-code to get these messages in the transcript.

Also attaching the memory map as seen in the summary.html of the entire system that i am currently using for the simulation in modelsim.

Question:

*How to restrict the malloc function to use free locations (that are not used by the boot code and rest of the main C code) in the SRAM region only* Or is there any other alternatives?