flagtest

#include <stdio.h>
#include <cstdint>

using namespace std;

int BIT(int value, int shift) { return (value >> shift) & 1; }

uint32_t lres;
int32_t sres;
uint32_t sr_n;
uint32_t sr_z;
uint32_t sr_s;
uint32_t sr_c;

uint16_t update_nzsc(uint16_t r0, uint16_t r1, uint16_t c)
{
	sr_n = 0;
	sr_z = 0;
	sr_c = 0;
	sr_s = 0;

  uint16_t value = r0 + r1 + c;

	if (BIT(value, 15))
		sr_n = 1;

	if (uint16_t(value) == 0)
		sr_z = 1;

	if (BIT(~value & (r0 | r1), 15) | BIT(r0 & r1, 15))
		sr_c = 1;

	if (sr_c ^ BIT(r0 ^ r1, 15))
		sr_s = 1;

  return value;

}


int main(int argc, char* argv[])
{
	uint16_t r0 = 0;

	do
	{
		uint16_t r1 = 0;

		if ((r0 & 0xff) == 0)
			printf("%04x\r", r0);

		do
		{
			lres = update_nzsc(r0, r1, 0);
			sres = (int16_t)r0 + (int16_t)r1;

			if ((lres ^ sres) & 0xffff)
				printf("add r0 %d r1 %d lres %d sres %d\n", lres, sres);
			else if (sr_s != (sres < 0))
				printf("add r0 %d r1 %d lres %d c %d s %d sres %d\n", r0, r1, lres, sr_c, sr_s, sres);
			else
			{
				int ov1 = (short)(~(r0 ^ r1) & (r0 ^ (lres))) < 0;
				int ov2 = sr_s != sr_n;

				if (ov1 != ov2)
					printf("add r0 %d r1 %d lres c %d s %d ov1 %d ov2 %d\n", r0, r1, lres, sr_c, sr_s, ov1, ov2);
			}

			lres = update_nzsc(r0, ~r1, 1);
			sres = (int16_t)r0 - (int16_t)r1;

			if ((lres ^ sres) & 0xffff)
				printf("sub r0 %d r1 %d lres %d sres %d\n", lres, sres);
			else if (sr_s != (sres < 0))
				printf("sub r0 %d r1 %d lres %d c %d s %d sres %d\n", r0, r1, lres, sr_c, sr_s, sres);
			else
			{
				int ov1 = (short)((r0 ^ r1) & (r0 ^ lres)) < 0;
				int ov2 = sr_s != sr_n;

				if (ov1 != ov2)
					printf("sub r0 %d r1 %d lres c %d s %d ov1 %d ov2 %d\n", r0, r1, lres, sr_c, sr_s, ov1, ov2);
			}

			for (uint32_t c = 0; c < 2; c++)
			{
				int oc = c;
				lres = update_nzsc(r0, r1, c);
				sres = (int16_t)r0 + (int16_t)r1 + (int16_t)c;

				if ((lres ^ sres) & 0xffff)
					printf("adc r0 %d r1 %d lres %d c %d sres %d\n", lres, c, sres);
				else if (sr_s != (sres < 0))
					printf("adc r0 %d r1 %d %d lres %d c %d s %d sres %d\n", r0, r1, c, lres, sr_c, sr_s, sres);

				lres = update_nzsc(r0, ~r1, c);
				sres = (int16_t)r0 - (int16_t)r1 - (int16_t)!c;

				if ((lres ^ sres) & 0xffff)
					printf("sbc r0 %04x r1 %04x lres %08x c %d sres %08x\n", r0, r1, lres, c, sres);
				else if (sr_s != (sres < 0))
					printf("sbc r0 %d r1 %d %d lres %d c %d s %d sres %d\n", r0, r1, c, lres, sr_c, sr_s, sres);
			}

			r1++;
		} while (r1 != 0);

		r0++;
	} while (r0 != 0);
}