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SDK Reference Manual
Application binary interface
Data is transferred between the mono and poly memory spaces using Programmed I/O
(PIO). For details of the PIO function, see [8]: The C Programming Language. This functionality is exposed to the Cn programmer by variants of the standard memcpy function.
The ABI reserves some words of poly memory as illustrated in Figure 26.
Address n-16
12 bytes
Reserved
4 bytes
PE number
Stack
Address 0
Figure 26.Reserved poly memory locations for a PE with n bytes of memory
13.3.3
Register model
The general register assignment is listed in Table 44 and Table 43.
Three operand instructions (for example, add r1, r2, r3) that use poly registers greater
than 64 (the upper half of the register file) are required to have an alignment of 2, which
implies that they are even and must be of size 2 bytes or greater. So any register argument,
r, to a three operand poly instruction must obey:
all (r <64) or (r modulo 2 = 0 with size (r) >= 2)
Document No. 06-RM-1600 Revision: 2.B
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