arm – Title: RISC-V: Runtime Exception with Syscall 9 Exceeding Heap Storage

I’m implementing a routine in RISC-V to allocate and initialize nodes for a doubly linked list. Each node contains:

A coefficient (4 bytes)
A degree (4 bytes)
Two pointers for the previous and next nodes (8 bytes each)
The total size of a node is 24 bytes.

Here’s the allocT routine I’m using to allocate memory for a node on the heap:
allocT:
# Size of a node: 4 (coefficient) + 4 (degree) + 8 (previous) + 8 (next) = 24 bytes
li t0, 24 # Node size in bytes
li a7, 9 # Syscall 9 for memory allocation
ecall # Perform allocation
beqz a0, alloc_fail # If allocation fails, return 0

# Initialize node fields
sw a0, 0(a0)        # Coefficient
sw a1, 4(a0)        # Degree
li t1, 0            # NULL value
sd t1, 8(a0)        # Previous pointer
sd t1, 16(a0)       # Next pointer

# Return address of the allocated node
jr ra

alloc_fail:
li a0, 0 # Return 0 if allocation fails
jr ra
#However, when I test the routine in RARS with the following setup:
li a0, 10 # Coefficient
li a1, 3 # Degree
call allocT # Allocate a node
#I get the following runtime exception:
#Runtime exception at 0x00400018: request (268697600) exceeds available heap storage (syscall 9).