Southco interview questions

Was contacted on Monday and interviewed by Wednesday. The hiring manager was pleasant and the conversation quite casual. All was going well until the subject of my previous salary came up. From that point on, the hiring manager's tone had changed dramatically and it was clear the interview was over. Feedback the next day was so negative I couldn't believe I was on the same phone call with this individual. HR needs to better screen the feedback they give to candidates as I personally have a highly negative opinion of this company based on this interview. A simple indication that they feel they need to see more candidates before making a decision would have sufficed. Instead, now my reputation with a very productive headhunter is ruined - seemingly just because the hiring manager felt my salary was out of line with what they could pay. Too bad - I had stellar performance reviews from my previous company and could have done wonders for them.