Added printf and stackrotate functions to VVS stdlib.

[vvhitespace] / stdlib / stack.pvvs

#ifndef VVS_STDLIB_STACK
#define VVS_STDLIB_STACK

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ Name:
@   stackrotate
@ Description:
@   Maximum rotation depth is five. Stomps on heap[9]-heap[14].
@   Assumes rotation depth greater than two, otherwise use SWAP.
@ Call Stack:
@   stack word n
@   ...
@   stack word 1
@   rotation depth (rd)  <-- TOS
@ Return Stack (n>rd=3):
@   stack word n
@   ...
@   stack word 1
@   stack word 3
@   stack word 2   <-- TOS
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
NSSVTSTSN               | Mark: 1010 (stackrotate)

@ For the convenience of other functions, modulo the
@ rotation depth by the available registers.
SSSTSTN                 | PUSH 5
TSTT                    | MODULO

@ Use heap[14] for generating register addresses.
SSSTTTSN                | PUSH 14 (ptr)
SSSSN                   | PUSH 0
TTS                     | STORE

@ Dump one word from stack to heap each pass through the loop.
NSSVSSSSTSTSSSSSSSSSN   | Mark: 00001010 00000000
SNT                     | SWAP
SSSTSSTN                | PUSH 9 (starting register)
SSSTTTSN                | PUSH 14 (ptr)
TTT                     | LOAD
TSSS                    | ADD
SNT                     | SWAP
TTS                     | STORE

@ See if the loop is complete.
SNS                     | DUP
SSSTTTSN                | PUSH 14 (ptr)
TTT                     | LOAD
SSSTN                   | PUSH 1
TSSS                    | ADD
TSST                    | SUBTRACT
NTSSSSSTSTSSSSSSSSTN    | BRZ > 00001010 00000001

@ Increment the loop counter
SSSTTTSN                | PUSH 14 (ptr)
TTT                     | LOAD
SSSTN                   | PUSH 1
TSSS                    | ADD
SSSTTTSN                | PUSH 14 (ptr)
SNT                     | SWAP
TTS                     | STORE
NSNSSSSTSTSSSSSSSSSN    | JMP > 00001010 00000000

@ The correct number of words have been stored to registers.
@ Time to read them back in rotated order.

@ First, prepare the counter in heap[14] again.
@ This consumes 'rd' from the stack.
NSSVSSSSTSTSSSSSSSSTN   | Mark: 00001010 00000001
SSSTN                   | PUSH 1
TSST                    | SUBTRACT
SSSTTTSN                | PUSH 14 (ptr)
SNT                     | SWAP
TTS                     | STORE

@ Second, read in the old TOS manually.
SSSTSSTN                | PUSH 9 (starting register)
TTT                     | LOAD

@ Read one word per pass through this loop.
NSSVSSSSTSTSSSSSSSTSN   | Mark: 00001010 00000010
SSSTSSTN                | PUSH 9 (starting register)
SSSTTTSN                | PUSH 14 (ptr)
TTT                     | LOAD
TSSS                    | ADD
TTT                     | LOAD

@ See if the loop is complete.
SSSTTTSN                | PUSH 14 (ptr)
TTT                     | LOAD
SSSTN                   | PUSH 1
TSST                    | SUBTRACT
NTSSSSSTSTSSSSSSSTTN    | BRZ > 00001010 00000011

@ Decrement the loop counter and loop again.
SSSTTTSN                | PUSH 14 (ptr)
TTT                     | LOAD
SSSTN                   | PUSH 1
TSST                    | SUBTRACT
SSSTTTSN                | PUSH 14 (ptr)
SNT                     | SWAP
TTS                     | STORE
NSNSSSSTSTSSSSSSSTSN    | JMP > 00001010 00000010

@ Return
NSSVSSSSTSTSSSSSSSTTN   | Mark: 00001010 00000011
NTN                     | RTS

#endif